I didn't get a notification either, so I highly doubt it's real. You might have malware.
As for being glad you used an "old junk password", that's worrying. You should NEVER use the same password anywhere to begin with, unless it's some random website that you'll prob never use again. Get yourself a password manager and make sure that all of your passwords are different. A data breach while really shitty, shouldn't be that concerning if you're using the internet properly.
https://haveibeenpwned.com/ lets you know if your email has been involved in a known data breach.