It's... not easy at all. Over the past 7-ish months I've gradually, but severely, lost faith and interest in the product I develop at work. Once I realized I no longer cared, and the only thing keeping me from quitting is a paycheck (a realization I only had about three weeks ago), I started taking the first baby steps towards switching careers to something more fulfilling.
It's easy enough for people to say "everyone hates their job, find fulfillment on your own time" -- but when working 40+ hours a week, and presumably sleeping 56-ish hours a week, that's a ridiculous suggestion. Nearly 60% of your life or more is meant to be unfulfilling and miserable? If that's true, then society is severely broken.
What I'm saying is, it's hard, and it shouldn't be expected. The fact that it's so existentially risky to try to find fulfillment in life is depressing and terrifying, but if it works out, it's worth leaving the misery behind.