Do you have it backed up?
Are you sure?
I read about an artist to whom this happened and not only didn't he back up his blog, it was the only place he'd saved some of his work.
If you use WordPress, there are various plug-ins that allow you to save the blog's contents and download it to your computer or the cloud. You can search "WP back-up plug-ins" to find them.
There's also a quick and easy-to-use Mac app called SiteSucker. I have it load the back-up into my DropBox account for extra protection.
This blog is on the Typepad platform and wasn't attacked recently when all my WP sites became the target of hackers, but no site is totally safe. If you think your blog is being backed up automatically but you're not sure, it's worth checking.