I don't know what to do with my life!?

I know that I am the only one who can/should make this decision but I am at a crossroad. I am eighteen and in junior college majoring in biology to become a doctor. But I don't love doing that. At least not the science/math part. I've recently developed a pion for writing and english. My teacher says that I'm great - right up there with her - but it's so unlikely that I could become a successful novelist or any other type of writer for that matter. I don't know what to do; I can feel the college application dates breathing on my neck while I wile away my limited hours trying to come up with my life's plan! I guess I'm not asking for someone to tell me what to do, just a little help or some outside guidance to ease my restless, worrying mind.