Why So Lonely?

Okay. So to start off i feel as if nobody in the world really cares about me. All the people that say they care, seem to never be there when i really need them. I know i shouldnt feel that way, but i always end up feeling that way. I wish i had a bestfriend i could just run to in my times of need, but ive never had a true bestfriend in my life. Maybe that should be my sign to just give up on the human race, but everyday i try to give up, there is just this one sign of hope that tells me not to. But im tired of that hope shining through if its always just gonna let me down. My question at the end of ever day is, why am i so lonely?