It's often very difficult to explain what it feels like to be on chemotherapy. When I was taking those treatments, going to work was sometimes extremely difficult. Working as a therapist requires strong interpersonal skills, acute attention and intense engagement with an individual.
I found it unethical to tell my patients I was going through cancer treatments, because it would place unnecessary responsibility on the patient to care for me and focus on me, rather than the other way around. So I'd have to lie when they told me I looked really tired, or distracted. And in between sessions, I'd sneak a nap on the therapy couch. I'd have to cancel my appointments due to dehydration and needing a hospital visit for fluids. I also in hour long session after hour long session after hour long meetings with nasty radiation burns on my bottom and genitals...sometimes wearing a diaper to keep the burn cream from ruining my clothes. All the while, coworker told me that they forgot I was even going through it all and I looked healthy. And I would go home and crash on the couch, sometimes sleeping for hours.
Chemo, to me anyway, feels exactly as I drew him: a huge, ugly, indifferent weight that could give less a crap about my plans for the day.