Ooh ...get you with your whistling kettle,lol
I would say that because he`s getting up and actually doing something, ie eating,making tea,watching telly etc that there isn`t anything bothering him
Whereas if he was just waking up and laying there staring at the ceiling or sitting on the sofa doing nothing, then I would say there is something on his mind
ps...when I let my dog out in the garden at 3am for a pee, sometimes he runs to the end of the garden barking, so I have to quickly run after him,he then thinks it`s a game and runs round the garden like a loony barking his nuts off.....not very amusing I can tell you, especially when it`s peeing down with rain