Welcome to JustAnswer Health...and thank you for your question. I am a verified Expert and am delighted to help you today. I think you became overheated and then began to get anxious. You did everything correctly, drinking the water,resting. Certain conditions can make one less tolerant to heat including thyroid disorders. I would recommend that if you feel like your heat tolerance is poor and if you continue to feel fatigued, see your Doctor for an exam and some blood work to rule out an endocrine problem.
So it is normal to feel exhausted the day after an event like this?
yes, it can be