I think I remember people saying that their school let people in without having had completed all the pre-reqs. They just had to complete the last class while attending pharmacy school.
Have you been accepted already and there is no way you can finish or is this for the next cycle? If it for the next cycle, can't you just take an extra full load for one semester and finish the class or do it in summer school if the school accepts those classes? If it is the latter, I'd wait until spring so your acceptance will be in hand already if you find that you can't make the grades you are accustomed to. Once you are in, all you need is to pass with a C.