A BAD DAY
I pressed 'command' and 'save' as usual and then closed the file so I could convert to word. Then when I opened it again it had changed back to the file I had 5 days ago. All the changes I'd made gone. Hodmandod Senior came home from work early to try and find it, but it hadn't even been saved on the autosave.
The only thing I can do is try again. They were, of course, the best words I had ever written...or at least better rubbish than the rubbishy ones I first put down.
From now on I am backing up every sentence.