Sending you a hug, @cloudybright. Given what you've gone through and the chemo, I'm not surprised you feel fatigued. Listen to your body and rest as much as you can.
When I lost interest in walking my dog and exercising, slept to avoid thinking about what I was going through, and in a way felt guilty about it, I decided to go to psychotherapy. It really helped to make me recognize that I had the right, so to speak, to feel the way I did and the therapist helped me identify what activities would help me start feeling better, little by little, embracing the fatiguing and finding non-forceful ways to work through it.