If you were writing drafts of multiple articles and were switching back and forth, it may be that the editor got confused and one of the drafts over-wrote another one.
What you can do is check the revision history of your drafts to see if one of your other article drafts is included there. This will be especially likely if you were using the “Save as Draft” button.
Please note in the future that it would be best for you to work on a single draft at a time. Once you are done, save the draft, and then navigate completely out of the post editing section and then back in. Do not ever click back as that can result in this type of result!