Is it possible for you to talk to a counsellor at school about all this? How about another trusted and sane adult relative? This sounds a bit to me like your parents are bullying you, and it's causing you to question your own self all the time and affecting your self-esteem.
Are they reasonable enough to listen to you when you talk to them calmly? try and just state (without emotion) how they make you feel. Maybe write them a letter?
I hope this gets better for you, I really do.