Stop, listen to some calm-ish, or nice music, and just find a place. Then sit there, and think of the future. Think of college plans, think of anything fun or interesting you hope to do this / next year. Think of some plans you should make with a few friends. Start talking to people who you don't usually talk to, like some people you've just seen around, but have never spoken to. Make some new friends, along with your older friends.
All of those will help a bit, your overall mood will improve, with time.