Something I heard from a wildlife photographer recently: you would be shocked by how much animals rest. Like, any time they can they just lay around. Barring certain seasonal events (like raising young or taking advantage of food), resting is almost all they do. You’re an animal too, and you shouldn’t feel bad if you need to spend hours or days resting.
The obsession with constantly working and being productive is a Protestant brain worm, not a natural state of humans. Take care of yourself and rest when you can if your body or mind is telling you that you need it.