One possibility is that the wrong card in your address book is selected as yours. Select your card in the Contacts application. Then select
Card ▹ Make This My Card
from the menu bar. If that doesn't solve the problem, continue.
Quit Mail and Contacts. Back up all data.
Triple-click the line below on this page to select it, then copy the text to the Clipboard by pressing the key combination command-C:
~/Library/Application Support/AddressBook
In the Finder, select
Go ▹ Go to Folder...
from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return. A folder named "AddressBook" should open.
Inside the folder there should be one or more files with a name beginning "AddressBook-v22.abcddb". Move those files to the Trash. Launch Contacts, then launch Mail and test.
If the problem is resolved, empty the Trash.