Parasympathetic swing?

Hi. I've had some sort of viral-induced, chronic fatigue, nervous system devilry going on since February. Today I spent the entire day at a meditation retreat, and took the first reading when I got home.

Then I spent the next few hours chilling in my pajamas, watching some Bridgerton, and when my heart started pounding, took the second reading. I'm still trying to figure out how to not trigger crashes, but so far it feels like I'm okay, and then I'm just... not.

Anyone else have this kind of change? If so, what tends to prompt it for you?