>> What made it a lot worse was that I was Greyhounding home, a 22 hour ride with three transfers. <<

Wow, that would do it.

>> The last con I went to, I made plans to stay with a friend in that area for a week after, to give me time to decompress from ALL THE PEOPLE YAY to 'mostly alone, but okay'. <<

Excellent plan. The slower rampdown makes it easier to cope.