Sundance,
Perhaps all the emotions of the day i.e., excitement, happiness, etc. taxed on you and your anxiety. Also, perhaps all the social stimulation triggered your anxiety. Sounds like you were a bit overwhemled for a short time. But it sounds like you did well to recover yourself and ride through the anxiety however unpleasant I am sure it was at that time. Maybe you can view this positively. Because although you did get a bit anxious you were able to ride through and let it pass.

Jennifer