This happened to me recently. It wasn’t a first draft (I had earlier versions saved), so I did have a few ways to reconstruct what I’d done. The whole put-it-back-together task would have been infinitely harder if I’d been in that first draft phase.
I’d spent several hours that day reading the vast majority of a 20K-word project out loud, editing as I went along. I thought I’d saved the file. When I came back to it after dinner, the computer had restarted. I opened the file only to find that everything I thought I’d saved was gone.
Here’s how I dealt with it:
Lots and Lots of Cussing
It’s fine to scream about it. Why wouldn’t you scream? There’s nothing worse than the feeling of losing a whole day. But then you have to put it all aside.
Don’t wait. Don’t think your mind will be better able to work if you’ve completely cooled off. Don’t give it a night’s sleep. You’ll forget a ton of it. Reconstruct immediately.
Think Big, Then Small
I raced through the sections, jotting down notes to remember the big strokes changes I’d made. Once I’d made those notes, I went into the sections and made the actual changes. Then I read the sections straight through (silently this time). And I could remember, as I read, where I’d made smaller changes.
Was It the Same? Nope.
But that was okay. I do think the bigger changes were tighter the second time around.
Point Is, I Didn’t Lose Anything
I don’t think there’s anything I lost permanently. No, it wasn’t word-for-word. But I don’t think I’d have remembered half of it if I’d decided to tackle it again the next morning.
And besides, by tackling it as soon as possible that very evening, I could go to bed knowing that I didn’t actually lose a day’s work.