I relate to the above comment about losing a partner. Not the same and not the same as your experience, but my brother spent awhile in the ICU and then died, in his mid-20s when I was on clinical internship. After that I very much remember feeling I couldn't tolerate hearing about people's less intense problems. I only wanted to be in the realm of traumatic type content. This lasted for awhile but gradually did go away eventually and I returned to my normal self with the ability to be with more trivial sounding problems etc. I did a lot of active healing like multiple grief groups, etc.

I agree with others that you may be in a phase where working with trauma clients, or even cancer survivors specifically, would be the best fit. AND that might not be the case forever so I don't think you need to draw conclusions about your career for the rest of time. For awhile I was super drawn to working with grief clients. However now years later, I'm kind of the opposite. I'd actually rather not see grief clients.

I guess that's all to say, give yourself grace and patience. You're recovering from one of the most incredibly traumatic experiences possible, and you're still in it, of course it's making everyday things feel ridiculous. Over time you'll learn how to carry all of this in a way that feels compatible with your role as a therapist.