I think that keeping as active as possible is a great way to help yourself through this process. I had a different chemo regime to you but found that walking and exercising helped to minimize the side effects. You do have to just see how things go as different drugs can have different effects for some of us.
I did a Pink Pilates course when I finished all my treatment and found it excellent to get me on the road to recovery. Great for one on one support and motivation. I felt like my physio was a good friend after a few visits. I think it helps to get your confidence and self-esteem back when you see the improvements that regular,appropriate exercise achieves.
I think we learn to listen to and notice more about our bodies going through all this. You will know what is best for you as you go along. Exercise is helpful but you may need to rest more as you go along. Hope that you can achieve your goal of maintaining or even loosing a little weight. I did end up putting on about 3kg (mostly fluid from steriods and chemo drugs) but lost this fairly easily when I finished. Wishing you all the best. Take care. Deanne xxx