This probably isn't the warmest advice but I'd cut ties with her. I get it. She's your mother. Still though, that isn't a blank check for her to be so nasty to you so often. You'll know what to do and when to do it and I hope it works out.

My sister and sister-in-law pulled a few doozies in their day. I have decided to write them out of my life and I have zero regrets. Life is too short to deal with mean and nasty people, even if they are "family".