I think scammers have stolen my domain and are using it to scam others?

I have been receiving numerous “failed delivery” emails from google, but I’ve never sent these emails out. Look to the second slide and you see someone named Addison Bargeman, this is not my name… but it says “From: Addison Bargeman <my email>” (I’ve blurred that out for privacy). It’s never from the same name, but always appears to be originating from my email. I’ve changed my password, but it doesn’t seem to let up. I’ve contacted googles support, but I don’t hear back.

I’m under the assumption that since I use a custom domain this may be part of the problem? I’m honestly not sure what is going on.

Any insight into what is happening and how to stop it would be appreciated. I can’t think of anything other than that scammers are somehow using my email or like spoofing their to look like mine? I wouldn’t even know how that works tho.