I feel you. I feel the exact same way. When I was graduating high school, I thought my life was over because I didn't know what I wanted from life and felt useless.

It's been a few years since then, and I still feel the same way. The most important thing is to never give up. I know it's easier said than done, but try. Put on music you like and try to write without judging yourself. Get lost in the music and the world you are writing about. I wouldn't worry about the future for right now. Focus on the present, and making yourself feel good (even for a little while) today. I know it's hard, I struggle with doing that too. Just find something to try to make you relaxed and feel better, even if it's temporary. I would try doing that, if you can, first.

Also: know that you are not alone. You are a part of a great community here! (I've been lurking for a while now, hehe). We'll all try to help you if we can!