Mellow, Or Lethargic?

So I'm in college now. I'm an hour and a half away from my partner in crime, Nichole. An hour and a half away from my family. I'm not "anti-social", but I'm not having as much fun with the people I'm with now. I've been told that I've become ever more mellow since I moved, and even though my "mellow-ness" is what characteizes me, I feel like it's become more depressed lethargy than being cool and mellow. I don't know why I feel this way, my life isn't bad right now, college is great, I love my classes, my roommate and I are actually getting along, Im doing real well. I don't know why I feel so ...down. I'm simply not as happy as I could be. Something's missing. Not just my friends, family, phone, and car. But something big. I kinda feel like I'm going nowhere right now. I feel like I'm just taking up space. Not doing anything important. I'm just a burden. I'm lost.