It's unusual for Clips projects to disappear after sharing them via email. Sharing a project shouldn't cause it to disappear from the app unless there was some sort of error or glitch during the process.
One possibility is that the projects might have been accidentally deleted or moved to a different location within the app. I would recommend checking the Clips app thoroughly to see if the projects are still there but perhaps located in a different section or folder.
If you're unable to locate the projects within the Clips app, you can also check your email to see if the shared projects were successfully sent. If they were sent successfully, you may be able to re-import them back into the Clips app from your email.
If you're still unable to find the projects or if they were not successfully sent via email, you may want to consider reaching out to Official Apple Support for further assistance. They may be able to provide additional insights or troubleshooting steps to help you locate or recover the missing projects.