Family probs...HELP!!!?

I have problems with my step dad...He yells at me every time he talks to me , It seems like thats the only reason he ever talks to me ... Every time he folds my laundry he will laugh and sorta cuddle with my bras... Every time he gives me a hug (wich has been alot lately) He will sorta grind against my azz and squeeze my ...I'm in my mid teens and i tell my mom but she wont beleive me ... What should I do besides going to the poleice????