Someone you didn't want to let go, but just drifted.
Without a doubt, this is my sorority big. (Yeah, I was active in a sorority for about a year and a half in college, deal with it.) She was/is the sweetest thing in the world, and we became friends that hung out all the time pretty fast. Once she graduated and had a really bad break-up all at the same time, she sort of disappeared for a while. Then she moved farther away, and farther still and got married and I saw her less and less. The last time I saw her was April, when she was about 6 months pregnant (and adorable, since she is about 5''2 and 115 pounds soaking wet) and now she's a mom and I haven't even met the little guy. Which I think about all the time.
We had some really great times together, and I wish we saw each other more, but older I get, the more life seems to get in the way of things.