Just two cents worth. Medical School is not the be all and end all. Some people, and I have friends in this boat, this is not a slag to anyone, find out that they are, for whatever reason, not cut out for medical school. One guy even got in with low grades, then decided it was not worth it and went to culinary school. My point is that we all get wrapped up in the notion that it is medical school or bust, when there are other careers out there that can be just as rewarding. If you are pulling those grades in first year courses, I would venture that without significant reasons attached, that perhaps it may be time to speak to an advisor about other professional options. I am not trying to shoot down your dream, but I saw far too many classmates at undergrad that muddled through and noone stopped them with some frank and honest discussion. Then they got through and had nowhere to go, since they did not think about the alternatives.
Once again, not to dump on your dreams, but if you recieved D's because you found gen chem difficult or were unfocussed, you need to examine your dedication. It is a long trip, and if you start out behind the 8 ball, it does not get any easier. That was probably my biggest pet peeve at undergrad. The advisors just let the students go, instead of actually ADVISING them.