Pregnancy:

Evidence which favours this diagnosis: 
    She is of childbearing age. 
    She is not taking OCP ("on no medication"). 
    She is presumptively sexually active.
Evidence that refutes this diagnosis: 
    High levels of estrogen in pregnancy suppresses, rather than stimulates, lactation/galactorhea.
    Pregnancy test all negative.
It is highly unlikely that she is pregnant. (99% sure pregancy is not the problem or cause of her symptoms).