If you no longer have access to the email address your account was created with, you can still log in using that email to update your account settings. To do so, you will need to be enabled in SMS messages, which will send the verification code to you via text.
Once you are enrolled for these messages, you will use that existing email to log in, and then put in the code that was texted to you. You will then be logged in, and can navigate to your Account Settings to update your email address.