Have had a few more insights into my particular sitch, which is very particular, since posting this.
What alleviates symptoms is to stop meditating - so I didn't sit this morning for even a moment. Sure 'nuff, been happy, cheerful, even-tempered, calm, and highly functional all day.
I miss meditating. But I can meditate and be a basket case for the rest of 23 hours, or I can skip it and be well.
I'm going to see about getting away from it for a month or longer (about the hundredth time I'm doing this, but, I don't see what else to try.)