On to my advice:
Decide on a project to build. Set a deadline you want to build it by.
All those other questions will fall into place.
Don't pick a project that is the next-big-whatever. Just pick something you can accomplish within, say, a week. If you want a list of ideas, I have a couple of links or I'd even be willing to share my list of (mostly non-trivial, hopefully profitable) ideas.
Doing a few projects small projects has turned me around more than once, and made me focused and proud of myself.
Your description resonates with me - physical exercise (a lot of it - back then, it was running 5-10Km 4-5 times a week, in addition to other gym visits and martial arts practice) seemed to be the cure. (Or, it was just coincidence ... who knows).
And I wasn't a sporty person back then, by a long shot - before I took that up (around age 20), I couldn't finish a 2Km run to save my life.
In this world there are 2 kinds of languages. The kind people like, and the kind people use. You'll find pro's and con's everywhere. Just sit down and do something, it doesn't matter how fast it is, how bad it looks. You'll have finished something.
It's like, here there's zero, and that's you sitting on the couch watching TV. Then over there there's nineteen billion dollars, and that's you being "successful". And in the middle there's nothing. And that's daunting and, of course, ludicrous.
Code little things. Or don't code, do something else. Go make something out of wood. But do it for the enjoyment, for the little thrill it gives you. Don't think about anybody else while you're doing it; don't think about what it might make you, or whether you'll end up on the front page of HN, or whether you'll get funding, or move to SF, or whatever.
Good luck. I'm 38 and your post resonated with me - this stuff doesn't necessarily get easier as you get older!