Have you ever considered that you might have a "narcissistic" mother? Mine acts the same way and she has all of the classic symptoms of a narcissistic mother. You can Google that term to find out more. The symptoms are:
Unpredictable way of relating - warm, but then goes cold; pouts for attention; cuts others off emotionally; won't talk or look at them, but will be sweet to the person standing at their side
Withholding - affection, attention, acknowledgement
Lacks empathy - teases, taunts, and berates another; gets irate and calls you sensitive when you tell them how it affects you
Critical - judges others openly, taunts, compares and ridicules and is relentless about it, but then can turn around as say, "Just kidding!" and "Boy, are you sensitive!"
Envious - cannot tolerate another person having what they feel they are lacking; could be anything from they are losing (which means, to an narcissist, that they, themselves, are slipping away...), and this can feel, to the narcissist, akin to death.
Narcissicism is nasty business.
Regardless of whats causing it - non acceptance and abuse such as what your mom is doing to you can wreck your life. At some point you just have to cut ties with her for your own well being and move on. I had to do the same with my abusive mother who told me that I am now a "sad caricature" of who I used to be, even though I am in a much better place than I was before.