Have you checked your e-mail lately. The Admin reset every ones passwords. You will need to save that assigned password, at least temporarily, to a document using your favorite word processor (Text Editor is a full version of Microsoft Word without Templates or Dictionaries so you already have at least one word processor application).
They, the admins, wrote a 'bot that randomly generated a new secure password and erased your old one. The new rules state that you can no longer have words (as recognized by a spelling checker) as part of your password, and it need upper and lower case letters as well as at least one special character (for you old schoolers ASCII Code above 128) to be acceptable as a password.