15 - 20 minutes isn't exactly a long way. I do a lot of walking in a day. But I know how you feel. Leaving my friends from my first Secondary School (Or High School) was hard. But it was a pathetic school anyway.
But if this is getting you down, find some time to see your friends. Like at the weekend, or whenever you have some free time. If you can't handle walking for half an hour or so, then a bike or a ride in the car will cut the length of the journey. I'm upset all the time, and hardly anything can cheer me up, but that doesn't mean that I can't help other people avoid this.
