I'm sorry. I'm a Sailor Moon fan / femslash fan (Haruka/Michiru, Makoto/Ami FTW) and I'm gay, but the gay came before the anime. My mother has gone through everything from "it's just a phase, it's just a phase" to "i would have sent you to different schools if it would have made you more normal" to flat out telling me that I wasn't gay. I think it's just a crazy mother thing to try and blame things on something else.

tl;dr Your situation sucks, and I'm sorry you're going through it, but you're not alone!