I dont know how much more i can take.

I have c-ptsd, profound depression, chronic anxiety and agoraphobia. I am completely unable to function. I can barely ever leave my house. When I try i start shaking really badly, I get really bad chest pains, I can hardly breath, the world starts spinning really fast and I feel like I'm going to die. I have flashbacks triggered by the smell of disinfectant, car doors locking, children crying, loud noises, police or ambulance sirens and sometimes just thoughts. Instantly it's like being transported through time and space back to some extremely traumatising events in my past. It seems if I give actual details here they get edited out so just imagine the most traumatising things you can imagine and you might come close. I can see, hear, smell and feel every detail of those events over and over. There so real I feel like ive been transported through time and space in an instant. Its really hard to tell whats real. At any moment I can reexperience situations that completely brake me. I haven't slept longer than half an hour at a time for months. Everytime I fall asleep I literally wake myself up screaming, sweating, heart racing so fast it really hurts and the pain radiates from my chest into my upper back. Then I'm fighting really hard for every breath and no matter how hard i try it feels like I'm not getting enough oxygen. I get so dizzy that the world starts spinning and it takes like ten minutes to realise it was only a nightmare but way longer for the physical effects to calm down. I regularly wonder if I'm dying from a heart attack. I live in my bed day and night. The only time I'm not in bed is when I'm pacing back and forward in my kitchen totally consumed with racing thoughts and a feeling of impending doom. Sometimes i pace for 14 hours straight without realising. The pads on my feet get so swollen and bruised from pacing on the tiles that it makes it hard to walk for days afterwards. I live alone since my husband died and I dont have any friends. I dont know anybody, so im completely isolated in my home. I've been on medication for years, ive been hospitalised multiple times and ive seen doctors of all kinds. Nothing helps. I have no will to live, nothing to look forward to, nobody to share my life with, no future, no reason to get out of bed or get dressed. I have absolutely no interest in anything, I'm simply existing. It sounds disgusting but even just having a shower is more than I can cope with some days. I have all my food delivered and I dont leave my house very often. I dont feel safe even in my home. I lock every window and everydoor. Even after that I have three locks on my bed room door. Everytime a possums walks across my fence at night (about ten times per night) I can see a shadow moving on my bedroom wall and it puts me into fight or flight mode immediately. I simultaneously want nothing to do with the outside world and am very lonely at the same time. Everything is just too hard. Im constantly exhausted from having very little sleep. Im sooo tired but I just can't get a decent sleep. I dont know how long i can keep going like this.