@Joleystub
Feeling a challenge to your mortality is extremely normal. Particularly if you have never experienced such a challenge before. An early diagnosis is always good and you have every reason to feel positive. Nevertheless dealing with one day at a time, one thing at a time, is excellent advice right now. It's easy to overthink. Or to spend time worrying about something that may never happen. Keep your valuable energy for the here and now.
However I spent quite a bit of time, a year or more after diagnosis, and when I felt well and confident, exploring my feelings about mortality, with some courses and reading, and found it very useful. We aren't taught much about that, it's not a popular chat subject! But it affects every one of us. Just something to consider later.
Best wishes.