Oh I'm surprised it hit you, too! But good to know, definitely makes me feel less alone out here. :)
Your guess on the distribution might be right, although we have absolutely no way of knowing. What's clear is that it happened from one day to the next, around Sept.23. They just pulled the plug. Things are slowly trending up again, though, so I'm hoping the reset is over. I do hate social media so I hope I don't have to take to Twitter to promote my writing, haha.
I'm still thinking about the Substack thing, haven't found the time to do it. Creating something from scratch on a platform with no newsfeed and essentially no discoverability, as you note, is a big investment in time and possibly for nothing. I have been thinking about maybe creating one for my Spanish language podcast, too, so that could be an interesting test.
So many plans, so little time. I'll try to keep writing here because I love the freedom, but we'll see what November brings along!