If they say in a way of a sentence, it would be; "You are a doctor"
If is a Question; "Are you a doctor?"
Tú eres = You are
what are you?
Well, first of all, it should be "ella es una doctora" and it means "she is a doctor."
"Where is the (female) doctor from?"
de donde eres = where are you from
you are
"Where is the (female) doctor from?"
It is masculine for "you are mean".
It's you
"Tu eres mi mundo" in English means "You are my world."
it mean "only you"
Eres bien mensa means: You are stupid/silly.