Why aren't I capable of identifying my self worth?

I'm not depressed. I already went through alot of that psyche analysis ordeal. I'm also not trying to win anyones sympathy. I just feel so blank. There's really nothing to me and I don't feel like i'm good at anything no matter how much effort I put into it. Ofcourse i'm good at some things but they're not important. I'm not good at social interaction, math, science, reliability, control of my emotions, and anything else that's valued and respected in society. I'm skilled at manipulation apparently yet I don't feel like i've ever intentionally tried pulling one over on someone.. i'm good at spewing random cool facts, I like writing songs and short stories, and i'm pretty much a recluse. Is there like a science behind making myself a better, more skilled person? Or at least a way to fool myself into believing I am?