So sorry for you health problems. They are very tough.
I also did not expect or plan to have cancer. Ironically two close friends had had cancer, I though statistically I therefore wouldn't. I nearly didn't have my regular mammogram because I was very tired and thought I was fine!
I find this a fascinating topic, how we all act as if we are immortal, it's so hard for me at least to keep in my mind that of course I will die one day. And that life can change in an instant. And every living thing is the same.
I think had to come come to grips with having had cancer after chemo and radiation finished, while it's gong on, I was so focused on getting through them, it was all I could think about.
Very best wishes for your treatment. Karen