You may have multiple Apple IDs and don't realize it. When you create an account for an Apple service, such as iCloud or the App Store, you create an Apple ID. You don't have to create a new account for each service—just use the same Apple ID.
Want to see if you have another Apple ID? Go to My Apple ID and follow the password retrieval process...
An Apple ID is the email address you use as a login for just about everything you do with Apple, including using iCloud to store your content, buying songs from the iTunes Store, and downloading apps from the App Store.
If you can't remember your Apple ID, you can find it by using the password retrieval process at My Apple ID.