I am so sorry to know that you are going through this. I went through the same kind of thing with my mom. All I can tell you is stick to your "guns" on this. Let her know that you will not accept this kind of treatment from her anymore and if she wants the priviledge of calling you her child, she needs to stop acting like that.
I wish that I'd been older when I went through my DF'ing and had to deal with my mom. Know that there are many here that care about you and know what you are going through, so stay in touch. I know your pain and wish that I could do more. I can tell you that you have friends here and we are here for you. I can also tell you that my mom and I are now close and have a wonderful relationship. She is not a j-w any more either. Her eyes were opened and she got herself out of the borg within a few years after me. So keep being who you are and in the end, it may be just that, that will help your mom turn it around and get her head out of her lower orifice.