I'm glad there was a reasonable explanation for what happened to you. As someone else pointed out, Undo is your friend. You lose the last 12 words (may be able to capture that by copying first), but get everything else back. I have gotten out of situations like this by not saving and just reopening the file.

I think a bigger danger is when you open files direct from an email to edit it. Especially if the email was opened from a web page (gmail, etc). I don't know how to manage file versions in those cases. It might be okay, might not. I make sure I save to my computer first in those cases.

I think you can find temporary copies of the file on the C drive if you know where to look. Here's a folder to try:

"C:\Users\YourUserName\AppData\Local\Microsoft\Windows\INetCache\Content.Word"