Depersonalization, which is essentially a form of dissasociation, is typcially a term reseved for serious psychological disorders, such as trauma disorders and various Axis I and II diagnosis with psychotic elements. I think it's better to leave terms like those to the professionals, if you know what I mean

From this side it appears you many have slipped into a waking sleep state, which despite sounding like a contradiction does happen on occasion as well as with narcoleptics. Sleep paralysis sets in, essentially freezing the body, however mentally everythings clicking away on the interior just fine.

As a psychotherapist, however, I'd be more interested in exploring the correlation between these two events, i.e. your wife walking into the room to ask you something and you suddenly freezing up, effectively shutting down any opportunity for a response. So... What would you said if you could have responded to your wife?...