While I don't disagree with what Q wrote, I guess I can offer the opposite perspective. Most days I have a blast. Like Q, I had a tough (in terms of hours) internship, but didn't actually hate it. There was a ton of camaraderie and everybody worked hard to watch each others back and carry each other along, with lots of gallows humor and joking 24/7. I feel like on this path there's always so much to learn, and never feel bored. Part of the blessing of coming to this field as a nontrad is that by the time you know enough that it feels stale, it will be time to retire. I get a kick out of doing all the things I never dreamed I'd be doing when I was a lawyer before I upset the turnip cart. Where else do they let you stick people with sharp objects, shove tubes and cameras up their noses, mouths and other orifices, do chest compressions until you hear ribs cracking, and not lock you up? The key difference is idealism. Folks in my prior field lose that faster than the average med student, so it wasn't really a shock when I saw all the things that disillusion some.
I thought house of god was a must read before going into medicine --it's an all too true example of residency life, (give or take the sex) -- the terms used by those residents are frowned upon, but the truisms hold up. You can't be idealistic, can't take things too seriously and always be humble about how little you really know or will ever know. And enjoy the ride. It's a crazy, hysterical ride if you have a warped sense of humor and can appreciate the ridiculousness of it all, and get a kick out of the cool moments that sustain you between the not so cool and dehumanizing moments.