I agree, with PeachCream, truth is the best way to go. If they were good friends they probably noticed you were struggling while in school anyway. Hiding our depression is never easy but people tend to sense it if they are around us a lot, so your friends maynot be so surprised. And yes, going to college even if it isn't your dream college is important. You will also make new friends. I hope you are getting professional help for your depression. Good luck to you.
Gayle