The same thing happened to me. When I was 13, I just suddenly started wetting the bed. The doctors still don't know the exact reason, but I keep on doing it every night. If you're going on a class trip and need a diaper to wear, I recommend Depend Refastenable Briefs. They don't make crinkling sounds like other diapers, so they're harder to notice. However, I don't think you should go on overnight trips for awhile.