Losing Weight! for teens?

I've been a fat kid since like 6th grade -_- so nothing new until i started "looking slimmer" (growth spurt) e.t.c i later found out that it was just me gettin taller lol.... now in highschool we just recently got weighed, measure, and I almost died when the nurse said yoou weigh 254 pounds!!!!!!!!! :( now IM ike freaking out not that it was a huge surprise because the year b4 that I was 233 IM I've always wanted to find ways to lose weight and as a teen theres NOTHING else to do but "play" or "excercise" which I just think those don't yeild fast enough results I feel like im stuck as a fat kid all of my life

IDK if this helps but im a classical singer therefore I must stay hydrated ( I drink water like crazy) take musical theater classes lots of dancing) plus gym class of course and commuting to skool ... I do things threw out the day just not enough I guess