You can recover deleted content using Version history.
On your computer, open your file.
At the top, click File


Version history

See version history.
Browse for the version that contains the deleted content
To find grouped versions: In the right panel, click Expand

.
When you find your deleted content you can recover it by clicking Restore this version


Restore. If you don't want to restore to a past version, you can copy the content, return to the current version and paste the content back. (To return to the original current version, at the top left, click Back

.)
All changes made to a file are saved to the version history. If work that you did on the file is not visible in the version history, it may be due to lack of connectivity at the time you were working on the file which prevented the changes from saving. Unfortunately, if you do not see the content in the version history, you will not be able to restore it.
I hope this helps and wish you luck getting your deleted work back. :-)