Ruby-
Like melancholy, I'm "just" an M1 and I agree that getting in was very difficult. Granted, I had some skeletons in my closet in terms of undergrad grades, so I had some hurdles to surmount, but many people will similarly attest that gaining an acceptance is a major milestone.
Personally, however, I don't think that Med School is comparatively "hard" per se. I go to school all day, study a lot but I still have time spend time with my wife, to work out, or to hang with my friends...I still have a "normal" life. In fact, compared to the "real" world of working and living, returning to full-time academia has been a pleasant change for me. (I used to be in the Navy, so I'm not sure that that experience is a fair comparison to the "real" world, but whatever.)
A couple of other things to keep in mind, though: Unlike undergrad, a lot of what you learn has a direct application. You simply *must* be familliar with anatomy and physiology in order to treat your patients. So far, a day hasn't gone by when I learned something that is relevant to being a doctor. I think this provides you with a better motivation to study than anything you had before.
In regards to tests and grades and getting those "A's", It honestly doesn't matter. When a patient comes in to see you, they aren't going to care what you got in biohemistry as an M1. They are going to care about getting better. Furthermore, you must also learn that sometimes, you don't have enough time to study to learn *everything.* You can't turn away a patient saying "sorry, I can't treat you, because I wasn't tested on that in school." You must realize that sometimes, no matter how hard you study, you aren't going to know everything. (It seems to me that this last point is the one that the "gunners" have a hard time coming to grips with.)
Success at Med school takes motivation, commitment and dedication.
Y'know what, so does success at anything.
Cheers,
-sb