1) Did you click a link from an email? 2) Does the page it redirect you to ask for your login info?
You may have received a phishing email. Are either true?
1) You expected this email because you were notified about it from another source e.g. website, support staff. 2) If you login to the website not via the suspicious link, the linked web page does not ask for your login.
If you answered yes, you probably don't have a phishing email.