Quite often than not a massive database of email addresses and passwords is leaked online. That means your email or password or both, could be hanging somewhere and might be used for bad reasons. For instance, with the emails and passwords out there someone could try to login into your website, email account or database. With the aid of softwares that tries thousands of passwords and email combos a minute, that could be an easy task for them.
The breached data goes on to be circulated in the dark web and might get messy for people who use the same password everywhere. So either way you might consider changing your passwords to stronger ones and using different ones for different platforms. The emails and passwords are uploaded to HaveIBeenPwnd database. To check if your email address is one of them, go to HaveIBeenPwned and for passwords go to Pwned Passwords.