Well, as you can tell...for me personally, physics wasn't my whole entire life. It isn't even what I love the most. I love math, history, sociology, psychology, chemistry, biology, kineisology, baseball, MMA, my wife, my parents, going to concerts and of course physics...all about on equal levels (more or less...maybe i love my wife and parents more...).
So therefore inorder for me to enjoy some of my other loves in life, some study might have had to be sacrificed, some mental/physical energy had to be spent elsewhere. I think this is OK. If your girlfriend is awesome and you absolutely adore her, PLEASE don't break up with her just to get all A's.
A person has to be balanced. Of course, there are people for whom physics IS life...they love it more than anything (and anyone) else, and that's OK as well.
Point is, never let one thing be your entire life, your entire identity. You are sure to burn out. Of course I've learned (through some of those Cs) that I do need to step my game up, that I do need to sacrifice time and energy away from some activities and redirect it towards school. For as much as I love a whole mess of other things, I don't think I could do anything else as an occupation than to teach Math and Physics at a Uni, to write textbooks in a different style than what is currently out there, to (attempt) to show that math isn't a tool for the physicist, but rather that the universe is a giant mathematical structure and physics helps us understand that structure in a less abstract way (I could be wrong, math may indeed just be a tool).
Long post, still long...don't trip too much over getting 4.0's. Go out there, enjoy your college career, study what you find interesting, work hard and kick *** to the best of your abilities. You'll be fine.