I was planning on PA school until June before my final year of college, when I decided I should consider med school and signed up for the MCAT. I actually applied to both PA school and med school, was accepted to both, and honestly considered both. I chose med school and am now halfway through my first year and am absolutely 100% happy with my choice. Although once in a while I think how much nicer it would be to be in PA school, that's usually only when I'm sick of studying or when the tuition bills show up. I'm sure I'll have more of these thoughts when I'm trudging through residency, but med school was definitely the right choice for me.
There are a lots of pros and cons to both routes in terms of length of training, debt load, salary, independence, hours, responsibility, paperwork, etc. I for one was planning on PA school because I want to have a family and I thought that the shorter and cheaper training and the easier hours were better for that (which they probably are). However, I have a pretty strong personality and would have had a lot of trouble being second-in-command for my whole life to people that I know I am as smart and capable as. To have people question my intelligence or skills because of the letters after my name would have been endlessly frustrating. And the last thing in the world I would want is to end up resenting my children someday because I chose to limit myself for their sake.
It's difficult to get an accurate gauge on how happy people are in each profession. Many PAs love their jobs and think they get the best of both worlds, and many others say if they had it to do over again, they would have gone to medical school. They are many doctors who love their jobs, but many others who are very bitter and say not to go into medicine. The grass is always greener.
You can absolutely 'help people' and 'make a difference' as a PA, probably as equally as a doctor. But you can also help people as a nurse, social worker, or teacher. There are many other aspects to consider. Talk to practicing doctors and PAs, think about what's really important to you, and most importantly, think about what kind of person you are and what will make you happy. if you're going to think "what if?" or "I could have been..." for your whole life then it's not worth saving a bit of money and time right now.