I had it when I got back from an extended trip to india one time.
People had told me that when I went to India it was normal for people to experience some culture shock .When I went there I had kind of mentally prepared myself so I was fine and had no problem like this but when I returned I got straight on a bus from heathrow to southampton then spent an hour wondering round southampton. The whole place felt empty of people and weird compared to what I had become used to over 6 months in india . That was my biggest culture shock experience I had and it lasted for a few days .
I think it is easy to forget to prepare yourself for your return to normality as most of the fun of getting ready for a trip/adventure is all around the trip itself and not around coming back to normal life
Horace Kephart 1906 " I know nothing else that so restores the buoyant optimism of youth as overhauling ones kit "