Why were my notes deleted when I permanently deleted my emails from gmail account. Can I get my notes recovered? My notes on Apple phone were lynced to Mac I am told.? Can you help
If you were syncing your Notes via your Gmail account (and not via iCloud) then Gmail treats them like a plain text email. If you delete your email, then you also deleted the notes.
Restoring from backup is your only bet - either a Time Machine backup or by recovering lost email.