How to prevent headache after playing soccer under the sun?

Most likely it's your personal problem. If your teammates do not suffer from a headache after playing a soccer game, it proves that it's your own problem. Drinking a lot of water and Gatorade before the game or sometimes even a couple of days earlier, will just prevent you from dehydration but that has absolutely nothing to do with your headache. My suggestion is to consult your trainer or family physician and they may be able to help you solve the problem.
I have been playing soccer for ten years and never have a headache after soccer games, neither do my teammates. That gives me a conclusion that your headache after the soccer games is a rare case and only your traniner or family physician can tell you why.

put a cap on yr head la...the best way i think

pour water over your head and drink a lot of water