Whew, eh? I urge you to approach more like a pro, though. When I realize I intend to make a major revision to a book, I never, ever change the original. I make a copy of the original and change the copy.
It’s going to happen again, probably: you’ll realize the way it was before you started futzing around with it was better, and you want to make sure to keep a copy.
Text takes up very little hard drive space, so save every draft. This could have turned out a lot worse, so I’ll just share your relief.
Maryn, who can store all drafts of a dozen novels at the free level of DropBox