I'd say that he can "sense" some change! Cats seem to know when things are going to change . . . and they don't like it!

I know whenever hubby & I have to be away overnight, Josie gets so affectionate & lovey dovey right before . . . like she knows we're going to leave her.

Just keep reassuring him . . . play with him as much as you can. He'll soon see that he's not going to get left out in the cold!