What does it mean when a guy calls you "sweetie"?

Do you only reserve such terms of endearment for those you care about or just anyone you might consider a friend? The guy I'm currently seeing, he texts me late at night last night and was like, "Night sweetie" (that wasn't the only time he's said that) and it was pretty random since the last time I texted him was around 10:30am and it was 11:30pm when he texted me "night sweetie". So I can't help but think that he was obviously thinking of me..