While I had TCH instead of AC chemo my doctor said the same thing about exercise. I was really worried I couldn't exercise. The reality is that on some days it just wasn't possible. Day 5 - 9 were my worst and very rarely did I manage to get out of bed due to extreme tiredness, achy and short of breath. I'd feel like I would never be normal again. Then I'd wake up one morning and feel somewhat back to my old self (except still will the breathlessness thanks to one of the drugs I am on) and be able to get back into the swing of things.
Listen to your body and rest if you need to. Don't beat yourself up if you can't exercise, you won't be like this forever.
Take care, Nadine