Two of my stories disappeared!

I wrote one story earlier today, saved it an all was good. Now, a couple of hours later, I'm writing another story. A little more than a thousand words in, the screen went blank, and the story disappeared. Gone completely. And the one I did earlier is also now gone. Additionally, my available word count has reset to what it was earlier today, before I wrote either of the stories. It's as if they never happened.