I know this is a late response but hopefully you're still following this topic. I think the advice give here is very good, and I'd take it, however I'd like to emphasize that your criteria for choosing a school should not be based on it's popularity (the so called "big schools") - regardless of the field you choose to pursue, it should be primarily guided by research interest. I cannot emphasize this enough!! It's not a job that you can force yourself to do it; you must really be passionate about it, otherwise you may end up miserable or even alcoholic (there a few such cases).
And I will add that particularly in Computational, good groups are spread throughout. Of course you have Martin Head-Gordon at UC Berkeley and John Tully at Yale, but you have have currently amazing work being done at Temple, USC, UMN, Iowa State, Michigan State etc., that are not considered "top schools." I just wanted to get that out there.
As for the MD thing, I come exactly from the same place. A lot of people give into their parents and do it anyway, so congratulations that you took the matter into your own hands. For me, the pressure was so big that I had to lie to my parents about taking the MCAT and applying to Med schools, even though I secretly had applied only to graduate schools. To this day they believe that I didn't get accepted, that's why I choose graduate school lol. It's not that I'm afraid to tell them, but I just never bothered because I know they'll get extremely annoying. Even now my dad sometimes asks me if I can still apply and drop out of grad school with a masters. It is a genuinely comical situation.