So, at school, everyday, I get so much discharge (I think it is), I'm 13 and I have to wear a pad and change it at least twice a day at school, its embarrassing, I wear a jumper all the time because it feels like I've peed myself, but I haven't, its clear and goes up to my crotch and behind and its so embarrassing, I don't know what is wrong!

Sounds like you need to change it more often, you change it before it starts getting that bad.