Could you please tell us how did you stop sharing?
Besides, are you using OneNote desktop app insted of OneNote for Windows 10?
I suggest you go to OneNote > File > Save & Backup > Backup Folder. Locate to this path, such as: C:\Users\Windows account name\AppData\Local\Microsoft\OneNote\16.0\Backup.
Please find and open the notebook name folder, check whether the backup files include the content that you need.
Here is an article you may have a look: 'Recover deleted notes'.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.