The most important thing is to have some goals to work towards to, that's my way of battling depression and keeping life on track. Don't just wait for life to sort itself out, because it won't. I once heard a motivational speech (after failing to get my dream job and feeling like a complete loser) that basically said that you've got two kinds of people: sprinters and long-distance runners. Some people are sprinters, they work extra-hard and keep pushing all the time, they achieve things fast and ride the wave of success. The other group, the long-distance runners, aren't as fast. They keep running and running, often times without even seeing the "finish-line", but the point is that they eventually get there, if they endure. 

Ok, moral of the story, what do these people have in common? They both have goals. And that's my advise to you: choose a goal and go for it. It doesn't matter how fast it takes you to achieve it, because the only person you're racing with in life is yourself. It doesn't have to be anything major, as others have said - get a job. That's a good first goal and will help you get on your feet. Money is one of the most important things in life, because it gives you independence, which opens up millions of opportunities. When you're getting money you don't have to rely on your parents and you don't have to abide by their rules.

And yeah, most people have this weird idea about "going to college". It's bullshit. Getting a degree doesn't automatically give you any skills or knowledge about a job. Also, not graduating college right away doesn't mean you've failed at life. Myself, I was in a pretty similar situation to you a couple of years ago, I had failed a lot of exams and things weren't looking up for me. I couldn't sleep at nights, I was really irritable and I even stopped RP'ing. So I thought "fuck it" and skipped 2 years in college (dunno if you can do that in the States), got a job, got an apartment, etc. Now I'm in college again and about to graduate and I feel fucking great. 

Get a job and stop stressing out. Stress and self-pitying are your number one enemy at this point. They sap any desire to work/improve yourself and just waste your energy. I know it's not easy, but you have to stop doing it. 

Also, do you do any sports? If not, start working out! That's a surefire way of battling stress.