in Monterey mac mail, all my sent emails disappeared

I apologize for the delay ... I apparently overlooked the notification. I set up a new All Sent Folder Jan 1 2022. It was all working fine thru January and most of February. Then, on Feb 22, I went to review an email I sent that same day and saw the entire folder was empty except for that single email. Thinking back, I'm sure I saw mail in that folder on Feb 18. Currently, the folder has all the mail I sent out from Feb 22 till today.

The folder had Sent emails from Jan 1. I sent out one email yesterday Feb 22. I looked in the folder today and the only email is the one from yesterday.