I have it. I did think it was food poisoning at first, but as it wore on, it felt more like a virus.

Started Thursday night. Came on really fast—like one moment I’m fine and then 10 seconds later the floor dropped out. No vomiting (though I really wanted to), but the bathroom stuff started yesterday afternoon.

I didn’t put 2 and 2 together OP, but one of my cats was ill over Christmas. Weird too. It’s not like goes and hangs out with other cats to get sick from. He didn’t touch his food for 2 days. Now I can fully sympathize.