This is the loneliest that I have ever felt in my life.. Watch
Not to mention societies. Join a society and you pretty much instantly have 50-200 people with shared interests.
So yeah, don't worry, things do get better
Friends at college or school are friends made by geographical location as well, you find that if your friend moves away from where you live, you lose contact as they begin to start making new friends. Here at University, you already live far away and so you actually make efforts to see them and not lose contact with them. That's just my 2 cents anyway.
Listen, your only in sixth form so don't worry about it. I'm 19 with no friends at all ever and I travel to Uni every day on my own. The only advice I can give from my experience is to have confidence in your own abilities, stand up for yourself and make the most of your opportunities at Uni.
Remember, it could always be worse. I wish you the very best of luck and would love to hear how you get on at Uni!