My cat is a pain in the butt

The last week or so my cat seems to be a real pain in the ass. Every morning around 4am he starts meowing like there's no tomorrow. He has water, food, litter is clean... but why the hell he has to howl at that hour?! Usually he meows a little and gives up, but the last little while he's been louder and more annoying. Anyone else notice any difference in their cats lately? Is it because there was a full moon? Or maybe it's because I was so busy with the recovery from my surgery, and then the wedding... he just wants extra attention. Well, now I'm wide awake, and the beast is snoring away on the couch.