You must keep in mind that taking the trade-off, that is choosing to get lower grades and have some fun, might mean that you lower your chances of getting admitted to medical school. Perhaps, I have drawn a bleak picture here. I think this represents reality. This, of course does not mean that to be a successful premed means that you will never go to the movies. It does mean though, that you will go to the movies MUCH less often than your friends and that you will find yourself studying when no one else is to be found within a mile-radius of you.
Choices have consequences .
If you make a choice to become a doctor, you should accept the consequence that you will have to work more than others. Keep your eyes on the ball and don't look to the sidelines. Take a look at GPA advice I give. For inspiration about medical school, you may want to read Arrowsmith by Sinclair Lewis. For a very thoughtful discussion of medicine and the role of doctor I highly recommend, Purposes of Medicine by Sir Theodore Fox.