I'm a massive introvert who spends most of his time coding, playing video games or Magic the Gathering, and my life has devolved 3 times into full-blown WoW addiction -- the fool's gold life people take on when they feel their real one sucks.
I have almost no friends, hate making plans and, generally, would rather be alone. "Hell is other people" is my motto.
And of course, this lack of relationships makes me very sad sometimes. The short term desire to be alone leads to long term sadness.
But here's where our stories diverge: I'm a tall, likeable (when I want to be), charismatic, good-looking, athletic white guy and can pick up women at will.
And yet, even though I can turn on the charm at will and get what I want (coincidentally, I'm a sales engineer), I'm still totally alone most of the time. This makes me feel like an outsider, an outcast, a loner, etc and the sadness can get uncomfortably dark.
So here's my point: As someone said earlier it's our desire to be alone that's the real problem, not what you look like or what your accent sounds like.
Introversion is a constant sabotage of happiness. If you don't maintain and work at friendships consistently over a long period of time, they will deteriorate. And doing that is nearly impossible for a "hell is other people" introvert.
The best solution, I've found, is to take the plunge and join a structured organization or group that you can't easily get out of. Being in college, specifically a fraternity, was the best time of my life. It forced me to be social and interact with other people, even when I didn't really want to. I think a healthy work environment with other people your age can help, too. It did for me.
One other note: I felt the same "Why is everyone else out having fun and I'm not?" feeling very profoundly in my mid-to-late 20s. It was a consuming, jealous, rage-inducing feeling. But now I'm 33 and I haven't felt that in years now. I don't even know why. Did I stop thinking that was a desirable thing? Or did I just give up?
TL;DR
1. Don't blame your appearance or awkwardness. The real problem is your short term desire to be alone. 2. Join a social or work structure that forces you to interact with others. 3. The jealousy of others' social activity should dissipate with age. Mine did.
p.s. Also, get off of Facebook. People are only posting pictures of their happy times, so all you get is an artificial stream of happy happy happy. This will inevitably make you feel worse. Facebook image crafters are probably just as unhappy as everyone else. They're working awfully hard to prove otherwise, aren't they?