In January 2019, a large collection of credential stuffing lists (combinations of email addresses and passwords used to hijack accounts on other services) was discovered being distributed on a popular hacking forum. The data contained almost 2.7 billion records including 773 million unique email addresses alongside passwords those addresses had used on other breached services.
In case you want to check for account that has been compromised in a data breach then visit https://haveibeenpwned.com/.
If Your Email Account Has Been Hacked, please do following:
1) - Please change your account password and it is always better to enable two factor authentication.
2) - Update your system with latest security patches.
3) - Scan your PC/Laptop with a good Antivirus System.
4) - You can change your Security Question.