Between age of 12 and 16 i had the same problem. I've been to the doctor for diabetes test, but it seemed to be something like urge-incontinence(i don't know i use the right english term, i think so) happy it wasn't diabetes. I've never wet the bed, and never worn nappies. Somethimes accidents just happends, nearly get used to it. After 16 it became less, and now i rarely get an accident. Good luck