Any ideas on what i should do?

I'm 16 and live with my dad and stepmom.they have been married for 9 years,and me and my stepmom have never really gotten along.she bitches at me about how i am a worthless son and that my parents made me by accident on a daily bases,and thats on for forgetting to do a chore or two.Sure i am not perfect,i screw up but i'm tired of hearing that.on top of that she snoops through my room when i am at work,opens my mail,email,and has to read any mail i send.And she does this all while my dad is at work.it's true your past will always haunt you.every mistake that i made when i was younger has made it impossible to tell my dad what she tells me.i mean she tells me that everyone is one her side and that there is nothing i can do about it. she tells my dad that i am a liar all the time,and seems to relish the oppertunity to tell my dad what i did wrong that day.also she tells me she doen't want me to hang around with my youngest brother,but yet tells my dad that i am ignoring my brother daily.