Further diagnostic reflection, however, leads me to one commonality between two of the (otherwise unrelated) individuals present: both have Attention Deficit/Hyperactivity Disorder (ADHD), as well as comorbidity with other learning disabilities. Considering my own mental capabilities, limits, and patterns of late, it's possible that my exposure to these friends, especially for more than a couple of hours, is more difficult for me to handle than under other circumstances. It's a hypothesis, anyway, though one I'm not eager to test with my sanity for confirmation.
May get my test anyway, or another one— Community Group is tonight, and being in conversation with that many people at once for a couple of hours is a daunting prospect. I'm a bit of a mess.