My acc was hacked

About two years ago my friend gave me his account because he got tired of the game and stopped playing and i had a blast playing my death knight getting all the different achievements and was proud of the char but since yesterday i was unable to access the account i havent changed my user name or pass but it said it was incorrect and i couldnt get it back because my friend forgot the pass for the email the email was created ten years ago when we were young now i don't know what else to do please help me recover my account