Apparently it's the most wonderful time of the year, but for many autistic individuals the Christmas season can be the opposite. Lots of social interaction, change of routine, sensory overload; it's a lot to process. I know from personal experience that there can be a long-lasting hangover. It's similar to waking up in the New Year and asking oneself what happened the night before, except in this case it's like coming out of a non-alcohol-induced coma which lasted 12 days.