It's good that you are purging all of these emotions but you can't stay in this self-destructive place. I've been there, done that - wallowed in the negative crap. after my ex left, I found an amazing therapist and worked through my issues hard core for a year. I came out of that able to have healthy relationships and to move on with my life in a positive way.

You need to love yourself enough to fight for yourself. No one else cares enough to do this for you. It's sad, but true. Even parents who actually love you can't do this for you. I know because my parents did love me - but they still unwittingly caused trauma because they are human beings and human beings screw up even when their intentions are good.

You have to make the choice to have a better life. The first step would be to cut off all ties with your mom. Sending her that letter - that was the definition of insanity. how many times have you tried to explain to her how she hurt you? Did she ever show any comprehension or caring? maybe she's an NPD, maybe she's evil. Who cares? YOU need to do what is healthy for YOU.

In your shoes, I'd declare myself an orphan, cut off all contact with family, and prioritize getting the therapy and help needed. Focus on loving and nurturing yourself. You deserve to love and respect yourself. Don't allow anyone into your life who treats you the way your mother did. I know it's hard to replace those patterns but you must do it if you are to have a positive life.