I had to take organic chem as a pre-req for micro. I am on my third year of school and finally just have one semester left to go. Here's the classes I have taken and the order I have taken them in:
Intro to A&P
Physiology (Fall '09)
At my school, you need your three sciences plus math, English, and Psych to apply. The problem with that is that you need to work up enough units to get an early enough registration date to even get into the classes. I JUST made it into Physio, I was so worried. I got one of the last three spots and I have taken all the above classes! Also, we need to be done with all our classes in the fall to apply the following spring. We can't be in progress, we have to be done before applying. It's been a tough process, but I'm almost there! We only have one application a year; about 600 names for 44 spots (some of those names are in more than once; it's a lottery system and your name gets added one more time each year you apply, up to 4 times). It's not unheard of to take 3-5 years before we even get into the program.
Sorry this is so long, just wanted you to know you're not alone in this crazy process. I can honestly say I am 100% sure I will not change majors, this is what I want to do and it's the ONLY thing I want to do. You'll have to figure out for yourself if it's worth it to you. Good luck!!