That happens to me...
In my case, I only figured out my problem after my son was diagnosed as autistic and started having the same problems I do. Too much going on = overload = shut down.
I can relate, it happens to me in crowds (particualy in grocery stores as well)....sometimes I don't due well in crowded places when I'm going through periods of heavy anxiety or I get overstimulated due to too much noise...As for what to due to combat it, I'm not sure wish I knew myself....luckily for me it only happens rarely when my moods are really unstable.
Not sure if it would of happened before then or not because I'd never been around that many people. I never did good around large crowds however and always tried my best to avoid them. I will let my psychiatrist know at any rate as I have an appointment with him coming up.
Yes that could be what you describe. I do experience it but its from a difference cause. Best just to inform your psychiatrist and think if it started recently in reaction to stressful events such as you have been mentioning or before then.
Also, does anyone else experience problems like this?