My mother is similar. We both don't have that much energy and seem to tire quicker than most people. I've tried some things over the years, done paid blood panel (not the most fancy one you could get), fixed my sleep, excercised etc. I think it probably comes down to below average genes.

The headaches themselves are from coffee (ab)use. But, without the coffee, I would succumb to fatigue earlier.

Right now, it doesn't matter that much. Luckily, through some smart choices (always aggresively going for the highest paying work I could get) and through frugal living, I've FIREd and now live a life of leisure, which seems to fit my disposition quite nicely. Not everyone was made to be a star.