Water water water. Which means of course the loo rather a lot! But it flushes it through and out. Exercise to get it circulating and to reduce side effects. Studies are showing the more vigorous the better. As @Eastmum said, chemo is probably not the best time to start a new exercise regime! But definitely don't drop your old one and pick up the pace when and if you can.
I was on TC, a 21 day cycle and it was only week three that I felt 'better'. Week 1 was a wipe out with fatigue, weakness and bone ache. Week 2 was tiredness as my body worked hard to make new blood cells.
Chemo is cumulative so sometimes these things can build up, but you get used to it, more or less, and the brain adjusts to this new (but temporary!) way of being.
We all react differently to our treatments so comparing ourselves to others has limited value. All I can really advise is try not to put too many expectations on yourself. Roll with the punches, pace yourself and cut yourself some slack. For most people chemo is a hard slog, but you'll get there. Big hug, K xox