How can I boost my self esteem? Please help!?

Whenever I look in a mirror, I tell myself I'm hideous. "/ Until recently, I started calling myself fat. My friends are getting a bit worried about me because I claimed bikini's made my stomach look massive, I hide food in my room, I sometimes starve myself, and sometimes when I go swimming I work past the "I'm tired" stage. I hang out with people who have a high self esteem and feel good about themselves, but I can't help but compare myself to others. I listen to inspirational songs that make you feel good about yourself. I try to raise my low self esteem but I can't. "/ Any advice??