You have both the right and the responsibility to protect yourself. If you need to turn that into a reason to take care of yourself that revolves around her it is:
If you don't take care of yourself, then you cannot take care of her. Her abusive mother left her alone for a week in the hospital when she was 9 so all I can think is I'm just gonna add to her trauma by not visiting. Any advice?
Uhm, call me dense, but how would that add to her current trauma? I'm assuming she has some abandonment issues, but that isn't your fault, after all,
you're not her mother. Some kids only see/talk to their parents on a monthly basis, or less. And don't psych wards come with therapists, so if it is a major issue won't someone be on hand to deal with it?
it may make little difference what you choose to do, because it is unlikely to be satisfactory. You must decide what will make you the most comfortable.
Too true. My uBPD mother can get upset over anything (real or imagined). Typically if I cannot make a birthday or miss something important I go with the "WOW, I am so sorry. I was so busy I didn't have time to---" Big apologizes and making it all about her tend to mollify the worst of it. Also, having people around helps. She pulls out the crazy less in public places. After all, it wouldn't do for anyone else to overhear the stuff she pulls. I mean, they might think she was crazy. Not sure if that would help with your mom, though. If she's already in a psych ward she might not care who knows she's got issues... .
Sorry, Mimi, it's a tough choice to have to make. Are you in therapy for the things you've gone through/the nervous breakdown? (You don't have to answer, but if you aren't in therapy, you might want to consider it. Most of us end up there at some point. There's no shame in needing help.)
SC