Recovering your energy after back-to-back teaching
Don't forget to eat and rehydrate. If possible, get out of your building to do so; that adds a change of pace, which also helps. Give yourself permission not to do anything intellectual while you fuel up.

When I have a schedule like that, I intentionally save relatively mindless chores for afterwards. Work gets done so I don't feel like a slacker, but I don't have to break my brain either.