I know that feeling all too well 
Do you think maybe its time you go back to the doctor nad have your meds evaluated?
When I was feeling very very low last year and was constantly thinking of suicidal thoughts etc I decided to take my health into my owns hands as my GP wasnt keeping an eye on me and everytime I mentioned anything to do with BPD you could see their thoughts going "oh dont start on this" and I truly felt I was not getting anywhere at all. I then saw another GP in my practice and was forthright and said how I haven't been managed by this practice at all and that I wanted to know if my meds could be evaulated. So she got me into a mental health clinic for the purpose of an evaluation (mainly for meds). When I did this I found out just how low a dose I was on and it was nearly trippled slowly. I spoke to the pysch and told him how I dont really have anyone looking after me and how often should my meds get evaluated - he said annually at least. So this is something I will do off my own back from now. Having the correct dosage helped my anxiety enough to get a hold on everything else so I was able to start making changes.
Reading your post really is a reflection of how I felt at this time and I hate hearing you go through the same thing, I know the hurt and the emptiness and the feeling like no one out there gives a shit, I used to feel scared all the time, I would wake up with an anxiety attack and go to sleep feeling very stressed. I guess one bit of wisdom my partner instilled in me is "if its not working try something else - dont keep doing the same things"!
I really hate to say this but the only person who can change things is yourself, I know how much we would all love for someone to rescue us and say it will be ok but in my experience this doesnt happen and you need to find the strength from inside some how.
Do you have something that makes you happy , a pet or friend you can confide in?
For me it is my dog, I love him to bits an dhe loves me and is always there when I'm down. Tobe honest for me it would be a lot harder without him.