About a year ago, I had a short stretch of time where I was super irritable in the afternoons and I couldn’t figure out why. Every day, as I drove to the gym, I’d experience a real sense of frustration and I couldn’t quite figure out where it was coming from. 

Yes, driving in Houston can be horribly frustrating, but this was different. My frustration every afternoon had become something that I had never experienced before. 

On top of that, I was feeling sluggish all day and I was horribly unproductive. No matter what time I went to bed at night—even if I took a nap, I’d still be tired. Because of this, I couldn’t focus and I wasn’t getting very much done most days.

I started to think through different possibilities of what could be causing me to feel this way and began to eliminate the things I thought it could be. I tried changing my diet, going the bed earlier, and a few other things, but none of that worked. 

I...