I thought (1) might prove a bit controversial. @akraticfanatic thanks for the pressure to clarify where I'm coming from, in case what I have to say is useful for others.
First, let me just agree that there are situations so difficult that nothing short of iron-clad, resolute conviction will get one through. But my goal in pursuing professional philosophy is to flourish, not just survive. And with flourishing in mind, I'd like to think that there is a golden mean to be achieved between cowardice (not even attempting philosophy) and recklessness (pursuing it at the expense of my own well-being). With (1) I was looking for advice on how to evaluate whether I am indeed flourishing as a philosopher. (Big thanks again for all of the guidance, people!)
My first experience with this sort of challenge was in building a technology company. I learned that some things are painful in a good way, and others are painful in a bad way. I also developed a skepticism of self-sacrificial attitudes (which are often perversely egoistic). One tactic I used to try to steer towards the mean was to set aside specific dates to re-evaluate my path. When I noticed things going poorly day-after-day, I set a date to allow myself full skepticism and compartmentalized my doubts in the meantime. This method didn't work perfectly for me, but I would recommend it to others nonetheless.