Weird issue - text & images mysteriously dissapearing

Hi there, suddenly I have lost around 10 pages of my InDesign document, no idea what happened.  I've tried restarting, and reopening the file a couple of times to no avail - anyone any ideas?  I've never seen this type of error before, basically the empty boxes you see used to contain text and images 😞 The rest of the 70 other pages are fine.

Thanks,

Liz