I want to be a CRNA, but the undergrad college I'm going to doesn't offer a BSN program, help!?

For a while I've wanted to go to medical school so when I chose the school I wanted to go to, I chose one with a good pre-med program, but now, I think that I want to become a nurse anesthetist and the easiest route to go is to get a BSN, but my school doesn't offer any kind of nursing program. Does anyone know what I should do?