Hey man I can relate to your pain. My mother is also a witnoid. I love my mother very much and after I left the cult I received a rashing of evilness like I have never seen from my mother. Oh she has done her evil deeds in the past to all my siblings and to me too but none like I went through when I left the cult. She hurt me deeply by attacking the very morals and beliefs that I hold so dear and close. You actually have had it pretty easy so far as much as I know about your side considering what I went through by my mother.
I never knew that my mother could be so evil but she is. All because I quit a cult ! So my dear friend I know just how you feel. My best advice to you is to just keep being who you are, be true to yourself, stand strong for your beliefs and hopefully someday your mother will come around. You should feel so lucky not to have a mother like mine but even through the fog I still love my mother, not because of what she does or does not do but because she is the one who gave me life.
I pray for you and I hope for you that you will find peace within yourself. Try to find forgiveness for your mothers actions and you will then find that peace within yourself and it does help you understand where she is coming from. It is a control from a cult and is not your real mother who has or is doing the things you are enduring. Pray for your mother and maybe she will be a different person towards you in the future.