If you genuinely didn't become at all bitter from multiple family members getting cancer, you should probably see about getting a psychiatric evaluation.
And thanks, but I am quite aware of my mental faculties, and have seen psychiatrists and therapists plenty; I have ADHD, after all, and recurring depressive episodes (though not true clinical depression).
Perhaps don’t assume that people who are different from you are… mentally ill? Seems a bit of an arrogant stretch. :/