I went through a couple semesters of nursing school. I hated it and quit and it took me 10 years of retail employment before I finally decided I needed to go back to school.
You have to have a special personality type to tolerate or enjoy being a nurse. The advice I received but didn't listen to was: "Be a CNA first, if you like that you'll love being a nurse."
I believe that you can still take around an 8 week class and then test to be a CNA. Maybe take it over summer break and try a part time job as one or possibly even a volunteer experience if you can't find paid employment in it.
If you hate being a CNA, save yourself the trouble of doing something you won't enjoy.
I had tried to convince myself that the short school time and excellent pay(at the time) was enough to get over the other aspects of nursing I didn't like, for instance, touching people, ever. I don't mind urine, feces and blood, but I hate physical contact with people.
Try to picture yourself actually doing the job, if any of it makes you recoil in horror, then it's probably not for you. Doesn't necessarily mean that pharmacy is for you either, you're the only one who can figure that out.
As far as prereqs they share, I took Micro and A&P I and II as part of my nursing pre reqs. Nothing other than that though that would count as anything towards pharmacy.