People usually say that you have to cut off negative people out of your life but how do you do that when the person is one of your parents?

Question

I can't deal with my mom anymore! She is the biggest bully in my life, always putting me down never happy with anything I do. I work, I study, I live by myself I pay my bills and im taking my drivers license. On top of dealing with criticism from society I have to deal with her bullshit aswell! Always telling me im not pretty, that I used to be but not anymore, that no man is going to want to be with me for years, when I was younger I started gaining weight after my dad passed away and she even told me that I looked discusting! I've been dealing with this to the point where I dont get fully naked in front of anyone! I have talked to her several times before but she always does it again, I have also been without talking to her for a while. Nothing seems to work! I havr tought about suicide before I just can't take it anymore and I dont know how to deal with this situation!

Ps: Any type of viscious comments will be deleted and reported so if you came to troll dont waist your time.