I go thru this every single time I am invited out somewhere. And, like you,once I am there, watching the play, eating dinner, whatever the situation is, I'm ok... I have to consciously work at tuning out the noise around me, but I eventually settle down.
And for me, I have just accepted that I put myself thru this every single time. I don't have to know the 'why' or connect it to anything, I just try not to fight it. If I fight it, the negative thinking starts... so I just try to get ready shortly before time to leave so that I am doing 'busy work' and don't think as much. I am more focused on getting ready, than walking out the door... yet sometimes, when I get out of the car and walk into my house, I start breathing again. Not realizing I have been taking shallow breaths the whole time... and yes I enjoyed the play, or dinner, or the company. And I am very much a 'people person'. Guess I have lived with it so long I try not to focus on it as being a failure, it's just part of who I am due to circumstances out of my control. I do take meds for anxiety, and will sometimes take something during the day of the outing.
But I also try to approach some of it with humor.... you are not going in front of a firing squad, you are going to a movie for God's sake.... reeeelaaaxxxx !!!!
Hope it gets better for you JMH... it's hell I know, but we have to have some kind of outside activities or we would all be fighting with canned food, right?? Lots of :hug:'s if you accept them. They are gentle :hug:'s..