I think people were right that I am stagnating and I feel the need for new challenges.

The catch 22 is that my job is so amazing that it gives me the newfound (newly realized) freedom to see the world while working. So I either stay, find some motivation to avoid the shame of not working, and keep travelling to fulfill my work/life balance.

Or I find a new job with new motivation where I'll be putting in more hours, more commitment and perhaps have less time for travel.

But regarding the energy, I take daily supplements of vitamin D and all the B vitamins, and I do feel that it does help.