I don't know man, I've got a lot of mixed feelings on this one. I've had one serious relationship while in college, and it just ended not too long ago. I'm all over the board, because I loved the girl, but I often found myself blaming her because I felt that I had so much less time for getting my **** together in preparing for the MCAT and some other things. But at the same time, I could've just been making excuses. She always said, "you make time for what you want to," and I thought, "shut up, you just want more time," haha, but in reality, I think she was right, in a lot of respects. Because looking back, she was an incredible support for a lot of parts of this process, and I don't know what in the world I would've done without her support. Weird and ironic, huh? You never know, the right relationship will add the right balance to your life, accordingly. If you think of it as a time burden kind of inconvenience, you found the wrong addition. The truly magical one will add a mix so that, the time she does "take up" is really time for you to refill on energy and relaxation, which should speed up your ability to focus when you do strap down on other things.....especially if you have a lot in common, then you're really not "giving up" anything.
I'm probably a huge hypocrite, because I'm trying to reignite the relationship right now, and I haven't even gotten an acceptance yet. Meaning? I don't know what's in my future, but I know there will be one, in one shape or another. Sucks to learn in hindsight, but you never know, sometimes it's a really good feeling to know that regardless, that person is going to be there with you every step along the way....that is, if you treat him/her right.
My 2 cents, I could go on forever with this. There is no right or wrong advice here, but I've found that the ABSOLUTE, MOST IMPORTANT THING you can do, is whatever is going to make you happy and successful in life, with a future where you see yourself realistically smiling. To that end, everyone has their own definition. I suggest renting the pursuit of happyness, haha