If your mother is constantly blaming you for everything wrong in her life is it ok to stop speaking to her?

My mother constantly blames me for everything wrong in her life... I just met her when I was 18 and she was fine till the past 3 or 4 years just steadily decreasing in attitude. I never cared about how she wasn't around my whole life I just wanted to be near her and she has always held something against me like if i was upset with her But im pretty sure she is the one upset... I just am so tired of the 3am calls about how i have turned my little sister against her... ( my little sister just turned 18 and is trying to live on her own) I am just there for my sister and what ever decisions she has and that pisses my mother off. And my mother has told my sister who i have only talked to once that IM a racist... and tried to turn her against me... Its these little things that are endless... But with that background Do you think that its ok to just stop Communication I have an anxiety and a heart murmur... I really shouldn't be getting upset so much and even with all that IDK If its ok to just stop talking to her I dont think its healthy mentally and physical to continue to take the abuse and forgive and forgive and forgive. Please give me a godly answer.