I'm so sorry to hear that, Dio!! If you haven't moved the hive, it might not be due to CCD, but the locals should know. It might be due to several reasons.
We lost 5 out of 6 hives over the last year, mainly because of a 2-year drought. One hive was a swarm that was caught, so it wasn't real strong to start with.
DH checked the remaining hive this afternoon. It is doing pretty good and looks healthy. He couldn't find any queen cells yet to do a split with, but put in a queen excluder, and will check again in a couple of weeks.
We've had to order new packages of bees several times. It seems like the price keeps going up, like everything else. It sucks, but the little buggers are kinda nice to have around! I hope we can keep this last hive going.