Suddenly missing many files that were there last time I used the iPad

A bunch of files, that were there last night, are suddenly missing or moved. I haven't used the iPad between then. I'm getting pretty worried and I would really appreciate any help!

I've noticed at least two apps can't locate their files. The Notability app has a list of my notes, but can't load the actual files. The Graphic app has a list of my files with placeholder icons.

I have iCloud backup off. iCloud Drive is enabled for both those apps.

Using the Files app itself I can't find any relevant files stored on my iPad. In iCloud, I do see my Graphic files, but they won't load on the iPad.

in Settings/General/iPad Storage the storage amount used looks roughly right. Notability using 222 MB. I'm really hoping that means the files are still there...somewhere? please?