Well, the panic has finally subsided. I worked all day Saturday and rewrote the missing stuff - or as much of it as I could remember. I came 585 words short, I think. A couple pages. I've now decided I will continue to write in my MS Word and then save to a memory stick AND to Dropbox. I still don't trust Dropbox, but I really like the concept of stuff being there if the computer gets fried.
Yesterday (Sunday) I worked a bit more, but had weird panic attacks everytime I saved the mss. I finally gave up and did laundry and went and got groceries, then swam, ate salmon cooked on the grill, and watched a movie.
Today Monday, I slept a little late, but the rest of the day I'm treating like a regular work day rather than a holiday. I'm rereading the book from beginning to end and fixing, tweaking, adding, etc. I plan to do this most of the day and then tomorrow as well, which is when (at the end of the day, thus not being late), I will email it to my editor.
Wish me luck. Because I sure want this book to be the best it can be, despite it's really rocky start and extremely crazy end where it almost vanished.