Back up careers in medical school falls through?

Next year I plan on taking a full year of science courses for pre-reqs. I am graduating with my undergrad this year, but didn't include enough of the pre-reqs because my degree is in Psychology. Anyway, what do I do if I apply to medical school and I don't get accepted? I will have a Psychology undergrad degree, and about 1-2 years worth of upper division science courses. Should I just apply for different programs at the same time? What other careers can I do with these credentials, or masters programs? I just don't want to put all my eggs into one basket, and end up with nothing.