Recovering data lost due to saving while in web layout mode

I twice lost all my data aside from the first page of a large file because I made the mistake of saving whilst still in web layout mode. As far as I can see, because it puts all the information on “one page”, when you save it deletes all but the first page. Is there any way to recover this data? I backed up, but when I reopened the document a new backup overrode it.

Writer - LibreOffice 5
English, Windows 10.

Please, after reopen the file, what happens if you change again from Web layout to Print layout?