Just wanted to second stayfly's suggestion of getting a part-time job. So many benefits, just one of which is increasing your social circle.
I found that it helped my schoolwork as well, because I had to schedule better!
I bet there are heaps of online forums and groups based on your interests - why not post and see if there are any members near you?
I would never have guessed a site like Steve's had so many members so close to me in Australia - and we have had quite a few offline meetings now!
Best of luck!