I felt the same a few years ago, but then I read Russell Brands autobiography. It actually helped me out in dark times. Probably because I thought it was a good idea to read something funny whilst depressed.
He's a crazy idiot but two quotes always stuck in my mind...
“My dad's philosophy was (and I think still is) that life is a malevolent force, which seeks to destroy you, and you have to struggle with it. Only those who are hard enough will succeed. Most people get crushed, but if you fight, in the end life will go, "Fucking hell. This one's serious. Let him through.”
“It's difficult to believe in yourself because the idea of self is an artificial construction. You are, in fact, part of the glorious oneness of the universe. Everything beautiful in the world is within you. No one really feels self-confident deep down because it's an artificial idea. Really, people aren't that worried about what you're doing or what you're saying, so you can drift around the world relatively anonymously: you must not feel persecuted and examined. Liberate yourself from that idea that people are watching you.”
So yeah......
I can't really give you advice on this one, but you're going to have to find your own calling. Mine so happened to be in the form of a book about drugs, struggle and hustle.
Good luck dude