Why does my 15-year-old daughter feel like everyone hates her?

She can't stand going to parties, church, or even just being looked at for this very reason. She gets embarassed over the most stupid, trivial things that most people wouldn't even think about. She's always talking about how ugly she is, and she is terrified of having to pray at church. She feels like the girls there, and also her YW leaders hate her, even though they have done nothing to make her feel this way. She is reluctant to pray in church, not only because she feels like the girls in her class are all thinking horrible things about her, but because she feels unworthy to talk to her Heavenly Father. What can I do to help my little girl?