I won't discuss getting back in or staying in medical school because I have no knowledge base there. What to do instead though depends on what you're interested in. Assuming you went to med school and are still interested in the medical field there are a lot of careers available besides the one's people usually think of like nursing or PhD, some fly pretty low under the radar so I'll just list a few, some obvious, some not so much. (forgive the over simplified descriptions on some)
Respiratory Therapist
Rad Tech
Bench Researcher Basic Science
Biology Instructor
*Clinical Laboratory Science/ Medical Technology
http://www.ascp.org/pdf/TheMedicalTechnologistandMedicalLaboratoryTechnician.aspx(if you like hands on lab stuff, but not bench research this is a great field, tends to be friendly to students with B.S. already. i.e. I had a B.S. in Biology, took a year of courses specific to the program like hematology, medical microbiology, parasitology, clinical chemistry, immunology, etc. that I was missing then did a year of internship/courses, and got a great job. Should be quite doable if you were capable of getting into med school. It's more directly related to patients than just working a research bench, also pays a bit better, and has just as much of a shortage as nursing does. Job opps all over. PM me if you want more info on this one)
*Cytotechnology- sorta like above but more tissue/histo based
* *Cardiac Perfusionist-this is the person that runs the ECMO or cardiac bypass machine. If you're the adrenaline junky type this might be for you. Usually requires two additional years of training, very, very high starting salary due to the stress, hours, and knowledge base required.
* Pathologist assistant- sorta like a PA to the pathologist, most are heading towards M.S. level training also
*Dosimetrist - does some behind the scenes stuff with the Radiation Onc. folks
Yeah, that's my two cents on other options on the med. related side anyway.