Ok, this is going to sound really harsh, and by all means, neg rep me, but seriously, stop whinging.
No one is going to hand you a life on a plate and you can't stay in school until you die, so you just have to get off your behind and sort yourself out. Is there some rule that says just because you've finished school you can't see your friends anymore? Why don't you arrange to meet up with them, or go away on holidays with them? And, as others have said, why don't you get a job? That'll keep you busy and you're guaranteed to meet people, plus you'll earn some money which means you might be able to go away on holidays at some stage.
You have so many years of life ahead of you (hopefully) and you'll go through so many changes in that time, some good some bad. If you're giving up now then you might as well just stock up your bedroom with food and live there forever, because this is probably the least stressful of them all (compared to deaths, marriage, divorce, children etc.). You're young and you have so many opportunities ahead of you. Things will never ever be perfect, you might as well accept that now, but you can make the best of everything if you have the right attitude and just carry on with things.