When I was studying in grade 10, my mom and dad went to Saudi Arabia to perform Hajj. In that year, the summer or autumn in Bangladesh was terrible. The temperature and humidity were too high that at home all my siblings got high fever. I have called our known doctor. Got medicine. I cooked for everyone. Every day I sponge everyone, In Bangladesh, we give water on the head during high fever. I did too with each and every one. I fed them. I cleaned the whole house. Did these make me tired? Yes, but I didn't fall in sick. Because I was following one thing.
Whenever you feel too much heat in your body, go to the bathroom and just take a shower. You don't have to put soap or shampoo every time. Do your regular bath once. Then if you feel too much heat. Go to the bathroom, take off your clothes, take a shower with room temperature water, wipe off your body and put your clothes on. It won't take much time but it will help you to keep your body temperature in good condition. You will feel better. I make my son do this. He doesn't like it. But he agreed, this makes him feel better.
This is my tip to save yourself from heatstroke.