Always glad to see other pharmacy students on the same route as I am. I'm third year and just decided last summer to switch due to same reasons. Pharmacy is a great profession but the profession is just not enough to satisfy me and keep me going anymore. It does sucks learning all the clinical aspects in pharmacy school yet may not be able to apply what you learned in real life.
I am currently in process of application process and hoping to enter in Fall 2012 when I graduate from pharmacy school. Alot of people say it hurts us to apply and change professions and whatnot, but I think that if you are really passionate about it, then you can do it. I wouldn't have advised you to take the backup plan and just stayed on medical school track instead. But I finished 4/6 years before changing my mind to switch there is nothing much I could do other than graduate then apply to medical school.
But I think there are a couple important questions you need to answer for yourself first such as what changes have you made since last application to medical school and why the acceptance to pharmacy school and the quick change of mind. If you can answer them and think you will be able to convince admissions, then I don't think you will have a problem as long as you have competitive GPA and MCAT.
So if you chose to drop out of pharmacy school, remember the drop out will not look good on your resume and you still need alot of volunteer, shadowing hours and research work to apply to medical school. Secondly, you still need time to retake MCAT and take another year to process the medical school applications, so what are you going to do in the meantime if you drop out?
On the other hand, if you stay hesitant to drop out and remain in the pharmacy program after reading the last paragraph, there is also some concerns. In the pharmacy school years they give you a load of school work and it may be alot harder than undergrad to maintain a competitive gpa, I mean it is a doctoral degree program afterall. So is it worth it to stay knowing your heart is not where its at, and possibly may affect your overall performance in pharmacy school that may ultimately lead you to never reach the path of medicine? Subsequently, if you stayed in pharmacy school you also have to fulfill many requirements such as IPPEs and APPEs, which are basically rotations at different pharmacies with different preceptors. They take up a lot of time and I can DEFINITELY tell you trying to apply to medical school and having to take care of pharmacy school requirements is not something easy to do. A lot of things may change in four years, your will to go to medical school may not be an exception.
But the one thing I can tell you about pharmacy school is that it does give you a lot of clinical exposure in the hospital and seeing patients in community wellness clinics etc. My pharmacy school even offers us a clinical research track in which we work with our own faculty mentor, write up a protocol, do our own clinical research project and submit for publication. All of these I am very thankful of for pharmacy school, for the experiences and teachings, and for letting me realize pharmacy is not for me which gave me the will and excitement to go to medical school.
So in conclusion, it is up to you. You need to determine your will to follow medicine. Because if you chose medicine and change your mind again, it'll be very hard for you to get back into another graduate program. So are you ready for a lifelong commitment to patients? Putting patient's needs before yours and your families? Are you willing to do hours and hours of paperwork outside of seeing patients? Oh yea, like one doctor said, 40 hours per week is really just part time for medicine. Hope this helped.
Edit: Sorry didn't see your last comment, so you will be going into P2 and trying to apply for fall of 2012. But most of the comments still apply.