I hate myself, but only when im alone?

i can be with a group of friends, even 1 friend, and you could never tell theres something wrong with me. i laugh i smile, im happy and the loudest one. And i love life that way. But when i get alone, and have time to think, i am always. always. so lonley no matter what. no matter who im with, dating or single, i always feel so alone. i hate myself for no reason. I'v never even been called ugly in my life, my haters dont even say im ugly. but i hate me, from inside out. im the only one who sees the things i do. Theres something inside me thats hungry for life. i dont know what it is. Im in serious need of something. It just tares me apart. And i dont know what to do. I always feel like im not doing good enough, like i have to look and be perfect. Im going to college next month, i have great plans for the future, i work hard. Why do i hate myself so much. For no reason.