Hi there! My name is Alison. I'm sorry that you're having this problem. I will do my best to help you resolve it. If you have AutoRecover turned on, you should be able to use the following instructions to recover a previous version of the file.
Choose File→Open from the menu bar.
Type AutoRecover or type a keyword or phrase in the Spotlight Search box in the top-right corner of the Open dialog.
Double-click the most recently saved AutoRecover file, or select the file and click Open. If you did a keyword or phrase search, use the Last Opened information to help you choose a likely file to open. If the file you want is grayed-out, choose All Files in the Enable pop-up menu, which allows you to open any file type.
You can also use Mac OS X Time Machine to recover any file that you’ve saved at least once.
Please give this a try and let me know how it works for you. If this solves the problem, would you mind taking a moment to rate my service? You can give your rating by selecting the stars located on the top right of the question page. I'd really appreciate it! Without a positive rating I am not credited for my answer. If this doesn't solve the problem be sure to let me know so we can continue troubleshooting.