iPad Pages lost after iOS11 update

I couldn't find a Pages document from October 2017 on my iPad mini (which I don't use very often) but could still see some older Pages documents (although definitely not all of them)...

I decided to update both the Pages app and the iOS on my iPad, and backed the iPad up.

Unfortunately after doing this, the Pages app is now empty...!

When I sign in to iCloud on my MacBook, Pages is empty and when I look for recoverable files, there are no Pages documents there. I am pretty sure the document I was originally looking for hadn't been backed up to the Cloud anyway i.e. only existed on my iPad.

My iPad is connected to Wifi and I have turned iCloud Drive on.

I am quite unsure where all my Pages documents have gone... Is anyone able to help? I saw lots of threads about lost documents turning up in iCloud Drive but mine have not!