I have similar feelings. Mostly, I'm waiting until college because hopefully I'll find more friends I can relate to, then I'll need facebook then.
I have an account with ~225 friends, only few I really know, others are just acquaintances. I can sympathize with the loneliness - unfortunately, most if not all of the acquaintances are really social, so it's one of the things that can trigger depression for me.
To be honest, I don't even know why I go on there. I can keep in touch with a few people I don't see anymore, and it's useful in some aspects, but nearly everytime I log on, I notice: No notifications, no friend/anything requests, no relation to anyone there... Everyone talking about how great the party was or whatever... what am I doing here again?
What's worse is that most of the acquaintances are people I knew when I was on the football team, so most of them are jocks/popular people that I barely know, who constantly talk about how great their social lives are, how great their friends are, etc... all these cheesy NT things that I don't relate with.