I need advice on a non-renewal vs. resignation

    I have been given the option of non-renewal or resignation
    by my principal. He refuses to give me specific reasons
    why. There are certain diffencencies in my teaching is all
    he will say. I have received a variety of pieces of advice
    anywhere from do not resign and fight it in front of the
    school board to choose another profession. I am a veteran
    teacher with 14 years experience and my first one in this
    district. Help!!! I am an excellent teacher with no black
    marks on my record.