This feels like my youth -- except I didn't give a crap about being alone. I didn't like how other teenagers did things that hurt their parents and destroyed their brain cells. But of course you just sound like you want to have a social life and just hang with people. I'm sorry to say that the only solution to that is to try. I'm nearly 26, and I have no friends to speak of, other than a few people I know better than I know most others.
I actually just read something that made me feel a lot better somehow. It was this book, Please Understand Me which describes a person's personality with the Myers-Briggs thing. I recently found out that I'm INTP, the most extremely unsocial and misunderstood personality group of the bunch, and only 1% of the population. It sounds like you might be this too. Reading about this personality type made me realize that it's actually sort of normal to be unsocial -- normal for the type, anyway. Read this and see if it's you. http://typelogic.com/intp.html
If it is, realize that social functions are just not your strength, and realize that you have other personal gifts to make up for it. If not, you still have gifts and personality traits that make you functional in other parts of society, like the arts or science or something. Apparently a lot of great people were loners, and it was this loner trait that pushed them to do great things, because they can't gain the satisfaction a person would normally get from interacting with others and must find other outlets.
1. Don't compare yourself to other people. It's never healthy. They're them and you're you, and you're the one that's got to live your life.
2. Talk to people at your job. Even if you only talk to them about job-related things, it's still a good way to get some socializing done, and maybe develop deeper friendships as a result. Also, directly choose to do something that will force you to interact with people. Like auditioning for a play or walking over to a group of talking people. Just something that forces you to look someone in the eyes and smile.
3. At the risk of sounding preachy, find God. Quite frankly, I'm in your exact spot right now (except I've been overseas -- hey, you should travel!) and if it were up to the world, I'd be a useless and kind of annoying pile of flesh. Because I know that God has a purpose for me, and created me to be the apparent weirdo that I am, then I know that it is to the world's benefit that I exist. I'm not a misfit, I just might look to one that doesn't understand.
4. America is a really nice place to live. We have so much opportunity over here, and on a daily basis not too much threatens us. We've got food, medicine, water, guns, benefits for the poor, all that good stuff. The trouble with a prosperous country, however, is that people get stagnant. We don't get to "fight" against anything, or fight for our survival. Which is why you should learn about a non-prosperous country (North Korea is a good example) or take up some kind of cause. And definitely exercise. Sitting in one place for too long makes the body ill-content.