You can try waiting a day and playing it again. The newer Pokemon games should store backups of un-corrupted save files, which might take time to restore.It appears somehow my Pokemon Ultra Moon save file got currupted. This might be a nonsensical question, but is there a way to return my file back to normal?
I lost 300 hours + over a thousand hours spend obtaining stuff from other games. I don't think I want to redo most of this again.