I've been in your situation too OP (BPD, OCD, anxiety/depression, cPTSD). I'm really sorry you are feeling this way. It is awful feeling frozen and stuck, when you know what you need to do... but you just can't do it.
Give yourself some grace. I used to count sleeping on the sofa, rather than in my room, a win when I felt this way - at least I had moved surroundings, plus the living room isn't as dark so it felt a bit less shameful to have spent all day sleeping there. I also tried to brush my teeth each day and drink enough water. If that was all I did, at least I survived and then at some point, it became slightly less bad.
When slightly more functioning, I then started the BACE method and wrote it down just to hold myself accountable.
BACE is where you do 1 thing a day in the following categories:
BODY - wash hair, do nails, do exercise etc
ACHIEVE - solve sudoku, cook new recipe, read 30 pages of a book (basically just complete a measureable goal)
CONNECT - speak to a friend, spend time with a pet, chat with a neighbour briefly outside in garden, etc
ENJOY - watch TV show or movie you like, play a game etc
Lastly I'm sure you are receiving therapy of some sort because of your diagnosis. But if not- go to the GP and sort out therapy- not CBT, proper psychotherapy. This is the only thing that made me able to accept living might be better than dying.
Good luck OP - this too shall pass.