First, make sure your doctor is aware of your fatigue. Yes, cancer fatigue is a common side effect of treatment, but not everyone experiences it for the same reason. There are several causes of cancer fatigue and it could be due to an underlying medical condition like anemia.
There are several things you can do to help fight fatigue, such as exercising, eating a diet rich in fruits and vegetables, and taking short naps throughout the day. Nutrition plays a big role in energy levels, so be sure you are eating a well-balanced diet.