What to do to regain my strength and energy levels

Afraser said:

Walking is what you need. You have not been exercising so you are simply out of practice - muscles get a bit soft, you feel every effort more than you used to. So walk. Set yourself a realistic target for week one - so many steps each day. Then increase the target! Repeat. As you get your body working more, it’ll be easier. Taking it easy during treatment can be helpful - but now is the time to get back into gear. Best wishes!