If you feel uncomfortable writing that then I should probably say I'm a MH professional.
But that doesn't mean I'm one that is frightened by, have a bad attitude towards people with BPD/EUPD.
In lots of ways, that diagnosis is irrelevant given all you're going through but I also don't want anyone to think I'm invading on their 'safe space' away from MH which is why I'm being honest.
So in many ways your previous diagnosis is irrelevant but it may possibly mean that you are more vulnerable to MH problems due to lack of sleep and stress.
So with all you've been through the last few months, most of that won't change in a hurry. No-one can solve all that or make it better so you shouldn't feel like you have to or feel you're a failure for not being able to just get on with it.
Let's go back to basics. To me, basics of MH is sleep, drugs and food. If you're not taking illegal drugs then it's sleep and food. If 'drugs' means prescribed medication then take as prescribed unless you have intolerable side effects - then speak to your GP/MH team.
Eat regularly and well. Even if you don't want to. Your body and brain can't function on little nutrition. Just a little snack every couple of hours. Toast, soup, beans, a bit of cheese, a couple of eggs or a piece of fruit. Something nutritional. Whether you want it or not, think of it as taking a pill - you don't want it but it'll be over in seconds. If you get into a routine of doing it, it won't seem such a hurdle.
Sleep. You need it. If your sleep is disturbed because of BF then reconsider BF. I know that's easier said than done but your baby needs a healthy Mum and if BF is preventing that then it needs to change.