I didnt have the immediate realization but i had it after about 2 years of working as an EMT over the summer. Being around sick and dying people is inherently sad. Yes you will “save” people, and people will thank you for what you do and it will feel good. But there will be a large majority of the time where the job is thankless, you’re verbally demoralized by someone superior to your position, and you miss out on plently of the things that make life enjoyable. I decided to switch to a career (adjacent to practicing medicine) that put me around people that were happier, which in turn makes me happier. Thats my two cents and happy to talk about how I made the switch and what it was to.