Don’t know what to do with myself! Since starting chemo and immunotherapy I don't really get any joy out of anything. Has anyone else felt like this?

Diagnosed with S4 Cholangiocarcinoma in Feb (bile duct cancer) they went in/surgery in May, closed me back up and been whacking it with chemo and immunotherapy. Mildly working! All in all, I feel fairly ok, but the boredom, lack of stimulation, with this sense of restrictive ‘semi-retirement guilt’ is a strange mental situation I just don’t know what to do with. I keep doing activities to “pass the time” or sit in gratitude with, along with friends and family, but it’s like I get very little joy out of much. I can look around, count my blessings, be in nature but feel the drugs are not just making me “blazé” to everything. 

Has/ is anyone else experiencing this? Are the chemo drugs just sucking away any “happy hormones”?