I feel so depressed... why?

I feel as if I have no talent. I can't sing or dance or nothing special. The only thing i get credit for is being smart... I'm gaining weight again... Im lonely, loveless, w/e.. I usually act stupid and say dumb jokes about people just to make myself better. I wanna feel good.. when I do, it doesnt last long. I'm a dreamer, but my dreams don't come true. What am i supposed to do? I feel like a big dope!