I always wish I was someone else?

Everytime I see someone who is super pretty, thin and is always laughing.. It makes me jealous. :/ For instance I saw a preview for Shake it Up! and the girl Bella is so pretty and thin. I feel so disgusted with myself. I'm ugly and super NOT thin. I'm overweight and am trying to lose weight but everytime I see someone prettier.. I feel discouraged. I also hate seeing people happy because I have a hard time at home and wish my life was 'happy'. My own parents don't even want me.. I can't learn to accept myself. I always have a flaw that I try to cover. Wearing sweatshirts, pretending to laugh, ect. I don't understand why God made me so disgusting and so un-happy. I don't feel like I will ever be pretty to others or happy. :(