Use a camelback, wear a soaking wet handkerchief around your neck, pound the liquids, eat right even when you don't feel like it, and sign your organ donor card. It sounds like you're already prone to heat injury due to physiology and your previous bouts with it. Every time you get heat exhaustion, you're more susceptible to it the next time. I.e. every time the heat makes you feel like crap, you'll feel like crap sooner next time. And heat stroke is a whole new level of jacked up worse than heat exhaustion. It's way more than not feeling right, full-on heat stroke is not too many steps away from dead.
Keep it up and eventually you'll barely be able to take the heat at all. The whole "I'm young and bulletproof" thing doesn't last very long.
SD
