Many people have multiple email accounts to keep mail separated for business and personal affairs. This can be frustrating when creating accounts for websites, such as Facebook, because you may not remember what email address is connected to an account. This can make it difficult to retrieve any email communications connected to Facebook. To determine which email address is connected to your account, you can visit your account settings.
Go the "Account" menu at the top right of your screen when you log in to Facebook.
Click "Account Settings."
Look under the "Email" heading. This is the email address you used to sign up for Facebook.
If you cannot log into your Facebook account, ask a friend to view your profile for you. Your Info tab will contain your email address unless you have that information blocked from friends.