If you have forgotten your username or password, you can have your login information sent to the email address registered. Simply go to the login page for your workspace and instead of logging in as usual, you should click the "Did you forget your password?" link.

Here you will see a text field, where you can enter either your username or your email address, and when you then click the "Reset my password" button, your password will be reset, and an email is sent to you with both your username and your new password.

Once you are logged in with your new password, you should make sure to change the password to a new one. You can read more about changing your password here.