Thanks for reaching out on the community. I'm sorry to hear about the trouble with your doc, but I'm here to help.
If your work is still lost, there are a few things you can do:
1. The document may still be there. Can you double check that you're in the correct account? Sometimes users will use single sign on while signed into a different email account, which can produce errors. I suggest that you make sure you've checked any and all Lucidchart accounts that might be under your email address(es).
2. Your documents might be hiding in your browser history. If you carefully look through your browser history when you last worked on the document, you might be able to find it. Simply click on the name of the document in your history and it should be restored to your account.
3. If your docs are still there, but not updated with your latest work, you can check the revision history. Please see this article for information on how you can restore from a previous version. Here's a summary of the steps:
* Open the document
* On the right-hand side you'll see an icon of a clock; click on it
* This will extend a window with a history of your various versions. Simply click on one of the previous versions to restore it
If none of these options work, please email the document name or URL to firstname.lastname@example.org. We may be able to locate the document that way.