I've just started college and I feel exactly the same.
It's as though I just don't have the energy to make new friends, because I don't know what to talk about, I'm not a very social person either, which makes it even worse.
I think the same way about acquaintances in the sense that what makes them from an acquaintance into a friend?
It did cross my mind that I could just be being lazy and irrational but I really lack social skills which most other people have.
I don't know if this would help but perhaps you could try seeing a counsellor, as they'll talk through things with you, and be able to offer better advice than most of the people on this including myself (no offence to the people who are giving advice!).
And pm me if you want to chat anytime.
Good Luck!