How can I retrieve my deleted iCloud account?

From: How to delete your Apple ID account - Apple Support

"What happens if I change my mind after I have requested that my account be deleted?

While your request is being processed, you can contact Apple Support [call them at a telephone number for your country --> Contact Apple for support and service - Apple Support ] with the unique alphanumeric access code you received, and we’ll help you cancel your request. After your account is deleted, Apple can't cancel the request, reopen your account, or restore your data."

How was it deleted? Do you mean you signed out of it on your device(s)? Or did you submit a request to Apple to have them permanently delete it from their system on their end?