Mikachu, I can REALLY relate to this. So hard. Hard enough that I'm still in therapy over it. All I can say is do not blame yourself, understand that she is very sick and that it's not your fault or her fault that she's doing this, and trust her doctors to do their very best with her. And it's okay to fall out of touch with her if it causes you too much pain. She has damaged you in some ways, but it's not entirely her fault--she is not in control of her thoughts and actions.
If you're worried about your things, go get them and bring them back with you. However, maybe you should leave the DBZ behind, since it is triggering for you... lock it up somewhere in the house where your mother won't find it if you have to, but you know better than anyone else here if you can handle DBZ again.
Hang in there!