I'll echo what a lot of my colleagues and OBP said.
I finished med school a couple of weeks ago, so I have a little bit better perspective on this than I did a few years ago. I think part of the problem with listening to the general consensus about medicine is that as a HS student, you're most likely shadowing really established, old-school docs, often people you know through the community/ your parents. I think the old timers are definitely more disappointed than the young people, because medicine changed so much during their practice. I have a family friend who literally saw his salary more than halve in the past 20 years, paperwork more than double, etc. Medicine as he had to practice right before he retired was a far cry from what he had expected, what had been promised to him, and what he experienced early on. So he was the first to tell me not to do it. But I think that's a pretty special circumstance, and I'd ask the younger folks, who probably had a better idea of what they were getting themselves into. Right now I have a fairly good idea of what my job prospects should be like, what my salary will likely be around, etc. If that were to drastically change soon, I'd be pretty pissed too.
Another issue, as someone pointed out, is that medical students (and by extension medical people in general) tend to be pretty complain-y. I think it's a result of constantly being in a bubble and having little contact with the outside working world on a regular basis, but we seem to believe that we're more put upon than anyone else. And in some ways, this is a particularly tough road. You'll study a lot, get yelled at and undermined and underestimated on a pretty regular basis and still have to come out stronger and better every day. Med school really is just the beginning, and just when you think you deserve good compensation and a little bit of a break, in comes residency to smack you across the face and make you feel dumber than ever. On a per-hour basis, we get paid around/less than minimum wage, which considering our years of education is pretty ridiculous. But it's enough to live on every month, and work hour restrictions have definitely helped ensure that we at least get one day off per week. Honestly, it could be worse. The problem is that because we're all in a bubble, we often don't realize how much worse it could be- or that our former college classmates aren't on a constant vacation either. Medicine isn't the only career that requires a lot of effort. The stakes are higher, but we're not heroes. We don't stay up for 4 days in a row, we're not expected to operate on dying people on our first day, we have some backup.
The debt: there's a lot of it. If you're smart, it won't be some crushing number like 350k, but when you're in your 20s any number above 200 bucks can seem like insane amounts. Loan money is monopoly money until you realize just how much you have to pay back, and that's a bad day. What makes me live with it is the fact that 1) I've never heard of a board-certified doctor that can't pay his/her loans back, and 2) there are government systems, like income-based repayment and the public service loan forgiveness program (at least right now) that help with this whole mess. Some jobs even offer debt repayment as a benefit. The situation isn't as dire as it may seem.
Ultimately, it's about the attitude. What i found fascinating in med school is actually the fact that the vast majority of people i talked to were really happy. Even the pissy, complainy, difficult surgeons- most of them couldn't imagine themselves doing anything else. My biggest piece of advice is this- don't let other people make you feel like you're supposed to see things a certain way when you don't. If you're happy, and you're not stressed, and things are going pretty well- feel that way. I think there's this mob mentality in med school where everyone pretends they feel the same way about stuff because it's the easier thing to do. But what that does is that it creates this false sense to the outside world that "all med students"/"all doctors" are a certain way, and that just isn't true. Not all med students are miserable all the time, and it's ok if you're not. On the flipside, if everyone looks like they totally have it together and they're just coasting through school, it's ok to be the one person who feels like he/she is drowning- chances are at least some of those apparently happy people are lying. At base, medicine is a job, it won't be terrible every day and it won't be perfect every day, you just have to figure out whether it's the one thing you can imagine yourself doing. If it is, then you can make it work for yourself (not all specialties are created equal!).