Love yourself anyway throughout this non-caring period. It will pass. All difficulties pass. Nothing stays the same. At a minimum, please walk every day. When my own lung cancer was removed, and I was able to walk further than a few blocks, I vowed to give my lungs and body an "oxygen flood" every day. I feel that is a way to keep those CT Scans clear. I believe it. It's also good for your mood and your brain function. Make a promise to yourself to walk. Make a promise to yourself to come out better than you even were before. And this may possibly sound far out to you, but there is a practice called Earthing (also known as Grounding) which is walking on the ground, preferably grassy ground. Or you could use a "grounding mat" in your bed or on the floor under your computer table. It lets your body connect with the Earth's free electrons and helps rebalance your own internal electrical systems. It is known to reduce pain and, so importantly, to reduce inner stress. When I do it, I can just feel stress rising up and out of me. Earthing also helps a person get a good night's sleep. There is a book all about it titled Earthing, and you can also find articles online about Earthing or Grounding--how it works and the benefits.
Next, don't let yourself keep giving you negative messages. Your self does not need that. Start listening to people like Tony Robbins, or Lewis Howes, or Jay Shetty. Then there's the functional medicine doctor, Mark Hyman. He talks about gut health and how it's related to brain health and pretty much the health all through your body.
That pain, yes, that would get you down. I see another way to treat it is with "cold therapy." I wonder if that would help.
Finally, that vaping. That cannot be good for your lungs. You could be making trouble there. I hope you feel better, soon. I am happy for you having had your cancer removed. That is a great thing! Me, too!