Lost Notes how can I retrieve my notes that I deleted by accident?

I don't know if Notes are kept in in the Recently Deleted folder. You can check:

Access iCloud Drive files from your iPhone and other devices - Apple Support - https://support.apple.com/HT203052

"If you need to access a file that you deleted within the last 30 days, you can get it back from the Recently Deleted folder in the Files app, or on iCloud.com. After 30 days, your files are removed from Recently Deleted." --> iCloud Drive FAQ > How do I get back files that I deleted?

If Limnos' post does not resolve the issue, you could try this:

1. See if your notes are still there on your email provider by using a web browser
2. If they are still there, delete your account on your iOS device and recreate it. This should recreate the Notes older.
3. If they are not, ask your email provider if they have a way to restore them. If they can, see step #2 to get them back on your device.
4. Lastly, you could perhaps recover them from a backup but note that if you do so, you will loose anything that was created after the backup.