I had energy reserves I didn't know I had and the same way I can hyper-focus on a topic to the exclusion of everything else I can also dig deep and have more energy than I ever thought possible. Why is this? The buy in factor.
I had this in school as well as I would tire quickly UNLESS it was a day where the subjects highly interested me. Okay, I understand we all have to do undesirable topics, but my brain has an all or nothing but in system. If I don't buy into what I'm doing I quickly tire. This isn't a choice thing; this isn't a "oh, I find this awfully boring so I'm just going to get tired now." Instead, it's a quick depletion of energy.
There is a flip side to this and that is that I can be oblivious to the exhaustion I'm facing when I have bought into something. This can go as far as forgetting to eat and sleep when I have truly bought into something. This can work for a while but eventually there will be a crash leaving me drained.
I'll be interested to see how the next 70 days go as it's going be an intensive time with presentations plus two international trips that's going to test just how much endurance I have.