College loans and medical school loans?

going back to college was wondering if it is possible to not only gat a college loan, but also a loan for medical school, or do i have to pay for the college loan first before ican get another loan. Like most students i have no money, but i can get a co-signer-I have never done anything like this before and any sugestions,help would be great- if you have experienced this before along with the whole medical school loan process i would be very greatfull if i could hear your story!