Is there an upside?
Yes.
We trekked West yesterday, and I was in the grip of a deep, all-consuming exhaustion. Funny. Once you pass thru the brittle, touchiness, edgy phase, you enter a bubble of calmness. All your energy, which doesn't add up to more than a drop or two, is used to "BE HERE NOW." Just "to be" takes every last ounce of your energy.
So, you coast. You flow. You float. You have No Energy to fret, worry, argue, to offer an opinion. You smile behind blue eyes. You are agreeable. Words come grudgingly. Your thoughts are focused on being present. You are a genial companion. You are malleable, flexible, seemingly content & happy. It's a bit of an illusion, you do not have enough energy to actually be anything except present.
It's a great state to be in to re-connect with folks you know. You experience them. Their energy overwhelms your own. And you just let it all come down.
So yeah, that certain exhaustion is very ZEN-like. You smell the roses. You go places with folks you know. You go thru the motions of being a person. You smile. You let other people talk and let their words roll over you. You exist. That's pretty much all you can do, and it's enough, and all is fine and good.