A lot of things drive me towards it. I grew up in a very working class family where we went through some really good and bad times, and academics were my focus during the good times, not at all during the bad. The period at which I fell out of academics was my last two years of high school and the two years after that. I always wanted to go to college but knew that I'd be paying for it myself, so I really didn't feel pressured to go and I'd lost that young academic drive that I later saw in a lot of really eager young college students. I'd changed a lot from the time where I was focused on school, so I studied what I wanted to know, not something that would lead to a specific career.
I've had a variety of jobs that simply generated money, and a few that were also greatly rewarding. At one of the jobs I met some guys that were in the same situation as me who were finishing post bac programs and applying to med school. Through them I got my first view of the type of people who do this, and as it tuned out, they're just like me. It didn't take long before I started looking into medicine as a career. So thats how I got here.
What keeps me going is what I've discovered since taking an interest. The more I shadow doctors, the more people I get to know who are either doctors or are in the process of becoming one, the better I feel about the choice I've made to give this my all.