Not just a southern pansy, Sergeant

Do angels brood? Or, perhaps more pertinently, can angels brood?¹

If they do, or can, there's a reasonable potential that Aziraphale is brooding. Even in the very earliest days of his business partnership slash friendship with Crowley, the two of them had a certain understanding. The Arrangement could never have sprung into being if they hadn't been able to communicate without words about it, given that they weren't allowed to communicate with words about it.

Something, now, is off. It's worrying at the edges of Aziraphale's awareness like a very determined moth trapped in a closet full of musty clothing.

He stands in the kitchen, staring out the window at the rather bleak winter landscape outside. He's holding a cup of tea in his hands, but failing to remember to drink from it. Every now and then he recalls its existence and warms it again with a thought, then forgets it again.

¹There is some sort of important philosophical distinction here surrounding the matter of what angels can do versus what angels should do versus what they, in actual fact, do. Maybe.