so I thought I would update.
I swapped out the sd card and it started working again.
I formatted the old one and it worked with that one too.
I found a few posts about people that had to periodically reformat the sd cards or they didn't get video that was usable when they needed it.

I guess this is how this camera lets you know it has some issue.
I have seen sd card needs to be formatted errors where it can't write at all, and the sd card is full messages, so I don't know why it wasn't covered with an error message, but who knows.

So assuming it lasts, I will add a reminder to format that card every few months just in case.

pretty sure I killed the old one I have, but might try to finish it up from the half taken apart state I left it in for a backup just in case.