Sounds like you already created an account with the second email address.
Log out of this account, go to the login screen. Type your second email in the box and click the blue continue button.
On the next page you should be able to get help if you forgot your password - do that so the password reset is sent to your email.
Then you can follow the prompts from there and you'll figure out the userid of the account your email address is assigned to.
