Whole session was lost

[Margaret5C19]

I know I have next to no chance of fixing this, but I was editing the last episode of a podcast series, and the session crashed. When I tried to reopen it, all edits have disappeared. Like, even renaming tracks, everything. I tried opening backups, earlier versions ... every single one is now an empty multitrack session. Many hours of work gone. Couldn't be more puzzled ... or upset. 

[SteveG_AudioMasters_]

When you say 'empty multitrack session', do you mean that everything's there, but just greyed out? And how have you got your backups set?