Yes I'm happy
Yes the hours are long sometimes - my specialty, Pediatric Critical Care, requires overnight coverage (which at most big ICU's means in-hospital shifts) and kids of course can get really sick on holidays and weekends so it's not like the ICU can just close up shop - it's not so much that the hours are long, but that there are so many of them
Sometimes the hours are boring, but I also chose a field that provides a bit more adrenaline rush than most and so when I'm dealing with a lot of not so sick kids, it's not as riveting. For the average office based specialty, it'll be a lot more even keeled. Most surgeons probably want their OR days to be pretty even keeled.
I wanted to be a doctor since I was three years old, and while I could have enjoyed other jobs that were my fall back plans, I like where I am now enough to say that I'd do it all over again. Having done residency in a kinda boring place and then fellowship is a much more exciting locale, I'd probably not follow that same path (especially after hearing the stories from my wife about her 20's in the big city - she had way more fun than I did at the same time) but the end was worth it. (and for the record, I loved my residency program, it's just in a place lacking social outlets).
It should be abundantly clear and stated in no uncertain terms that going into medicine requires sacrifices for you and your family (your parents and whatever sort of family is in your future). As an undergrad you'll sit through 3 hour labs and end up studying on weekends while your friends in the business school are at the bars. The MCAT requires a lot of preparation. In the preclinical years, you'll be poor and living on student loans while those same friends from the business school are making real actual money. You'll spend many hours studying for exams and shelfs and USMLE's, while they're travelling and going out. You'll miss holidays and important events while in training because someone has to be at the hospital and you average only one day off in 7 most months. You'll spend 3-7 years or more, making the same amount of money as many of your non-medical friends, but work 2-3x the number of hours per week that they do.
And when you're all done, you'll still likely work 55-60 hours a week (more than most people), you'll still have some sort of call schedule that will carry the chance that you'll have to abandon plans with friends, family or kids to go take care of a stranger (especially if you're a surgeon or other specialty that's more hospital based). Oh, and you'll have patients die. You'll be acquainted with death in ways few people are. Even general pediatricians get phone calls from someone like myself in the ICU letting know that their patient passed away.
From where you are now, you should keep up your exploration of careers. Then you can begin to weigh the sacrifices they require and if you think you can manage them.