There's no need to rationalize the stress, it just is stressful. "Ability to be stressed" doesn't really apply when it's an entirely different thing, with different things making you stressed.

I don't think I found corporate politics funny until I had a pretty good nest-egg of savings built up (nothing crazy, about a year of living expenses).

Your other worries, I would talk to a therapist or at least someone better than me about. A lot of ourselves flows from our jobs, and it sounds likes it's got you.