Well I was also apprehensive of revealing my illnesses to my friends (I decided to keep it hidden). But if you're afraid of your whole school knowing about it after you tell one friend, well are you sure you wan't to tell that one friend?
Hell, I understand wanting to express yourself to close friends, but I've been burnt by people I've told my ailments to, so be careful who you do reveal it to, people who don't understand can be judging folk.
Also QLD boy! Well I'm a Sydney boy.