If you were affected you would be logged out of your account and you should have received a notification from Facebook. Log back in and change your password and setup 2 factor authentication.
Two-factor authentication is a security feature that helps protect your Facebook account in addition to your password. If you set up two-factor authentication, you’ll be asked to enter a special login code or confirm your login attempt each time someone tries accessing Facebook from a computer or mobile device we don’t recognize. You can also get alerts when someone tries logging in from a computer we don’t recognize.
See this article here to setup 2 factor authentication for Facebook: 2 factor authentication Facebook