It sounds like the decision is already made. But if not, you might consider this:
From everything I've seen, medical school - especially the 1st two years - is very different from the typical job of being a doctor. After these years, you will NEVER sit anywhere for endless hours staring at the same thing.
So if you don't like school now, there's every chance you'll like being a doctor. You won't know until you try, and you'll need to get your degree to do that. But if you finish, and still don't want to be a doc, your MD degree is still very useful.
There are good reasons for not finishing school. Just make sure you have one before you actually "do the deed", or you'll regret it forever.
I worked for a few years before going to school, and the corporate world was boring and so underchallenging, esp bec I only had a bachelor's deg. Then I looked at my manager - the classic "middle manager" - and thought "after 10 years, if I'm really good, I'll get THAT cubicle and do THAT job? Forget it." I don't like much of school, but it sure is better than the corporate rung.
Hope it works out for you.