Ladies with auto immune/ health issues that affect your energy levels. How do you fix the feeling of headaches, pain and just feeling absolutely drained when you overdid it?

I did about three hours of gardening today and I feel like death now. I tried to take a nap but it was also so hot it was such an uncomfortable nap. I woke up with such a headache which I took painkillers for, but I'm still so so so tired.

I made sure I drank enough water and I worked outside of the hottest hours.