Another suggestion that will all but insure that you never have this problem again is to get an offline blog editor such as Windows Live Writer or BlogDesk (both for Windows and free) or something like Ecto for the Mac (reasonable at $17.95).
Basically what they do is allow you to work on your computer, and they save your blog posts to your computer and even allows you to add tags and categories. When you are ready to publish, you hit the button and it automatically uploads your post to your blog. No muss, no fuss, and no hiccups causing you to lose work. You can even put images in them right on your computer and the software will upload the images and when you go to your blog, there is the post, the images and everything right where it should be.
I'm on a Mac and I use Ecto for almost all of my posting and in two years I have not lost even one sentence, much less an entire post.