I have received emails saying my domain name was deleted, yet when I check my Cloudflare account, everything seems fine.
November 4th email said, "The zone: “-” in account: “-” was deleted by Cloudflare on 2022-11-04T19:38:17.455756Z.
Can you tell me why I’m receiving these emails?
Opted-in or it’s “by default” as it should be a notification for the owner of that particular CF account or a member of another one.
Have you shared your Global API key with someone or over some 3rd-party integrator, or in some plugin like WordPress, etc.? 
Kindly, navigate to the Audit Log from Cloudflare dashboard and take a look for an events, I believe you this could help you to find out what happened with the domain name
May I ask have you used Cloudflare for that particular domain withing some 3rd-party partner/integrator since before?