I fell strangely alone?

well it all started last year when me and my girlfriend separated. Ever since then I've felt alone. I look around me and i see people who have at least a couple of friends, people who they can share their feelings and emotions with. I have no one to communicate with. I mean yeah i do have a great sister who has just left school and do get the chance to talk to occionally, but thats not the kind of lonliness i'm feeling, i have no one my age to talk to. I see people at school hugging and pulling and whispering to eachother in the corridors and it makes me wonder why cant i be like that, why cant i be normal and have friends like everyone els. PLEASE HELP!