Hi OB, and welcome to the forum - I'm so glad you found us.
I am so sorry about your mother. I could even say your "so-called" mother, because it's not just this visit, and it's not just recently, is it? Those of us who had reasonably normal parents can't even begin to comprehend the hell of growing up with a mentally ill one.
But you are going to escape your past, I just know it. How insightful you are to find the irony in having to visit her while you are working on your TMS journey! And you are reaching out to help others, which is awesome. I really liked something you just posted a little while ago, which I also thought was very insightful for someone else.
The best advice I can give you is to not take your mother's behavior personally. It is her behavior, it is her mental illness, and it has nothing to do with you.
The healthiest thing you can do for yourself is to accept and acknowledge the rage that your inner child must feel at how unfair it is that she is incapable of being a proper mother to you - that she has NEVER been a proper mother to you! You absolutely SHOULD have a huge amount of rage about the fact that by having you, she was supposed to make a lifelong commitment, to love you, and to nurture you, and to protect you from all harm. Not only did she not do any of those things, but she caused you harm, which is NOT ACCEPTABLE.
You don't have to say any of this out loud to her (it wouldn't do any good in any case) but it would be powerful to put it down in writing.
You certainly don't have to hate her, because she's clearly mentally ill. She may herself have been abused as a child, causing irreparable damage.
You can forgive her, but you do not have to forgive her behavior, because her behavior is not acceptable.
Above all, you can love yourself, for finding a different path and choosing to make this journey, and for joining and participating in this supportive community.
And please, know this in your heart: you deserve to heal!
~Jan