If you need a folder back that you had deleted previously, you may recover it.
Navigate to the Admin drop down menu.
Click Deleted Folders on the left hand side of the page to see deleted folders rather than deleted files.
Click Recover on the far right hand side of the table to recover the folder.
Note: The folder will be sent back to where it was in the structure, with the suffix _DELETED so you can easily identify it. You may want to change the folder's name once it is recovered.