I see your other expert is not online and you are waiting.
It sounds very consistant with heat exhaustion. Heat exhaustion symptoms include, dizziness, fatigue, chills, low grade fever, nausea, headache, feeling faint, weak-but rapid heart rate, and several others.
Treatment would have been to get into a shady (preferably air-conditioned room), drink plenty of fluids, take cool showers/baths, take Tylenol, and rest. Sounds like you did all the necessary things, and if you are feeling like yourself today, I would say you are ok. If not, I would see my Dr for an electrolyte status check (done via blood work).
Things to look for that would have called for emergency care would include irritability, confusion, or unconsciousness, or his heart rate becomes elevated (over 100 beats per minute) or he fainting, as this might have been an actual heat stroke.
Heat exhaustion can occur at any time....even if you think you are drinking properly. So, next time you play gold, try to put yourself in the shade if at all possible (when you can) and as often as you can and take plenty of breaks.
Hope this helps!
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