You may do better than you expect to. Chemo is unpredictable and you can have good rounds and bad rounds with no rhyme or reason why. I think most of us have at least a few days each cycle where there is enough energy to get a surprising amount done. You may be really lucky and skate through it with little trouble at all. Ive found getting up early and crashing in the afternoon works best for me. Anyway, nothing is going to change through worrying about it and, as I can tell you, general disarray can be distressing but rarely deadly. You can clean up later.
Hating that one lonely boob is understandable. It's not small stuff at all. The whole business sucks but the alternative isn't great. Good luck.