You are pre-med. You should not be spending every waking moment in the library. If you are, I'd say you are doing something wrong.
There's nothing wrong with exploring other career options. However, to quit college after 1 year is probably not the best idea - unless you are having serious problems (failing, academic probation, family problems, etc).
It is natural to feel this way after your first year of college. It is normal to question your motives, to feel burnt out, and to want to do something else for a while. Actually, I experienced something very similar during the beginning of my second year of college. Your freshman year moves a mile a minute, with new friends, new situations, adjusting to a new routine, harder classes, etc. Sophomore year, when you come back, things tend to "stagnate." You no longer have the novelty of freshman year, and it is easier to feel isolated, become homesick, miss family and old friends, and so on. However, you get through it, and the feelings pass. It's silly to throw in the towel if all you are feeling is a little stress and insecurity over your future goals.
I think it is, in general, a bad idea to quit college this early on. It may seem like just a "break" or a "leave of absence," but many people who leave with the intention of returning never actually come back. I watched a handful of people fall off the path during undergrad. Most of them never returned.
Also, it's a bad idea to quit now, because you have very few marketable skills. Finding a job that adequately pays the bills may prove difficult, especially given today's economic climate.
It's not imposible, though. I watched a close family member of mine quit after her first year of college (due to poor performance). She took several years off to work, took some community college courses, and got her act together. 8 years later, she graduated from a great school as a double-major with honors in both, crushed the GRE, and landed several amazing PhD program offers. It took her a while to get there, but she finally did, and is now very happy.
If you were able to handle freshman year, you'll be able to get through the next 3 years. Take a lighter courseload next semester. Take some courses that are not pre-med. I think that your best bet would be to stay in school. Just stop spending all your time in the library. It's OK to be pre-med and still have a life.