Your username is the same as the email address you used to register your account.
If your password isn’t working, you can reset it using this link, Reset your password.
If you type your password incorrectly multiple times, you may see a message: "You've entered the wrong password for the user too many times. You've been throttled." This lock-out is only for a short period - you should be able to try logging in again after a minute or two.