Gday @NightFury bloody hell mate that's a lot going on at once. I reckon too you are in a combined burnout AND depression because quite frankly, you have received a lot of bad news all at once so, not only have you had your future drastically reconfigured: and you are going through the diagnosis stuff.
I am not formally diagnosed but there was a point in my life living with another diagnosed ND person I saw the similarities and started living my life through ND expectations and found that it got a lot better, also "returning to myself" as I was a very eccentric child/teenager/20s and it was TRYING to fit into society that made my life terrible, so I quit trying to fit in and just kept to being polite and being decent to others to keep and maintain social bonds.
RE burnout strategies and I definitely relate to what you say, when I am burned out or about to, it feels like my arms and legs are too heavy to move.
#1 is try to lighten the load on your mind. For me this is just DISCONNECTING the non-stop stream of thoughts and problems, just forcing them to stop then lying in bed and sleeping A LOT.
#2 eat healthy do not overload on sugar, caffeine etc, go the opposite way and fill yourself with salads, eggs, meat, other things that properly nourish your body and brain. Vitamins and supplements, but dont go kooky and excessive into "detoxing" or "buying marketing fads" just take a full rank of multivitamins.
#3 Cut out EVERYTHING thats not the bare minimum to sustaining life.
#4 Try to resolve and forget what it is that is so heavy on your mind, because I find my mind is like an octopus choking itself sometimes, all the tentacles are tangled up in its own 'body' so try to find why, and unplug whatever that is, truly resolve the conflicts and that includes deciding what something is, and how to approach it. IE last burnout for me was working with a boss who blamed me for EVERYTHING, I spent a whole weekend in bed just chewing over why I wasn't responsible for EVERYTHING and figuring out what HE was doing to be unfair to me. I figured out a conversation and a plan of action, and decided I was going to approach the problem that week - then I got sacked which ultimately saved me from the situation and proved my thoughts about the boss.
Option A I could believe all his BS that EVERYTHING was my fault and I was a shit employee,
Option B I resolved it in my mind I was a good employee and he was terrible at delegating and managing, that he was trying to do all the work himself to prove that he was the boss against his own ego, that he did NOT want to hand over power and he was terribly insecure. His problem not mine, it took about a week to fix that up and believe in myself, then I fell into a cycle of IM USELESS AND BROKE and had to resolve that too. "I am not useless and broke, i had a crap job for a short time which was frustrating but like how I got that job I'll just go back to applying for every job that i can see until I land one". I dont stay within one industry or within my specific training, I find that too frustrating I just apply for every job that I think I can do including whats within my training and background. Yes there's a lack of progress but I'm not a career person, a job gives me money for life it is not my life.
#5 tell anyone who's useful that you're burnt out and half dead but dont bother trying to convince unhelpful people.
#6 I do this thing where I forget all of "my life" and I just walk around in a grey tunnel of nothingness. Then I sorta stare at "my stuff", my eccentric hobbies and I have found that when I start to snap out of burnout it's a process of reconnecting to "my life" so, my goal is to hurry this process up as I forget my own life very often and lose A LOT of time and progress. I am a very object based person, my life is filled with STUFF that means and does things for me.
So early phase I might just stare and look at my stuff for a long time. For example I have a dragon statue which I really love, I bought it when I was out with one of my very best friends, we studied together and also worked in a chinese restaurant, together. One day we went shopping and we each bought a statue, mine was a brass dragon. So when I look at that statue it brings back 4 years of being best friends physically close, and 12 years of being best friends. It can be very powerful for me to just stare at that dragon and think of all the great things we have done and what the dragon represents. That helps me snap back.
Then there can be something which is very overstimulating such as going to the shops, going to the beach, it feels like those two activities kinda jolt me back into proper conscience then it feels like "I am back within my true self". especially at work or in conflict it can feel as though real me drowns inside reality, and I get overtaken by other people's expectations and my desire to please the situation/keep the job/fulfill the obligation that I NEED to do. For example a job interview I might obsess over it for a week until it happens then I feel relieved I completed it successfully. I am slowly learning to prepare failsafe methods so that I can "live my life" and also "fulfill obligations". I do all of my obligatory stuff in advance, pack a separate bag, plan food, allocate clothing, run through the actual day in my mind. Then its planned and I can also perform my "real life" which is playing in my junkyard.
#7 work and disorganisation, I love having a regular job it keeps me very grounded, I know how much time is used to make money and how much time is left over for me. I currently dont have a regular job, my work is all over the place which is very stressful, including budgeting and "being poor" so I have put an anti-routine into place, which involves exercise, cooking and cleaning at home. Not just milling around staring into space feeling stressed. Resolving long term problems and short term problems too, for example I was spending $150/week on food now I have cut it down to $80/week by planning meals and buying all the ingredients and....FORCING myself to cook even if I don't want to. Instead of being stressed, eating out and avoiding the dirty kitchen in my sharehouse I have found that I am reconnecting with my housemates, yes I hate the dirty kitchen but I have partially cleaned it which allows me to use it without doing the cleaning on behalf of lazy filthy housemates.
Thoughts - paranoid, divisive, angry: They are such filthy lazy people I hate the kitchen and I am bad at cooking so I will eat out all the time.
Resolved thoughts - connecting, compassionate, constructive: They are all ND too and I really hate that they don't clean, and I refuse to clean for them so I will clean a small patch, I will pile their dishes in a heap out of the way, I know that the fridge is clean and decent so I will load it up with healthy food and I know that my own pots and pans are clean, and I have worked in worse commercial kitchens so I have to do what I need to do which is cook at home, not sabotage my life, waste my money and create a crisis. I know very well that it is easy to run away from anxious thoughts and it is hard to stick with constructive thoughts, but every day, every year I try to improve on last year and all of my shortcomings so when I cook at home I will be better at cooking and also keep in control of my finances.
Thats all I have time for now but I wish you very well, think back to last time this happened and how you got out of it. Keep building up a "library" of self knowledge and strategies to keep your life on track, and always think back how far you have come. I love to think back how far I have come, especially on a bad day as I have COME A LONG WAY!! Theres a saying "your challenges of today are your dreams of yesterday" and when I occasionally think **** my life I especially think back to when I did nothing but smoke and live under domestic violence/victim complex/denial I actually feel so happy to recognise I kicked most of that out and turned my life right around to the point where it is unique, cool, difficult, challenging but also it literally is my dream life even if my brain whinges about it, the brain used to whinge about needing to smoke more before going to bed, now it whinges about something else so....guess what....MY BRAIN IS A CONSTANT WHINGER!! And I have learned that and I try to just shut it up and keep moving.
Take care "THIS TOO MUST PASS" and it can be very helpful to stay in touch with counsellors, friends etc to help you keep talking and thinking about whats going on. But beware of pity parties they dont go anywhere, you need to stay still/moving sideways but never go backwards. All the best.