Maybe he is hoping to get rid of you because of the leave you will get during and after the pregnancy. You will provide zero output during that time. I would ask for a meeting immediately be it face to face or a call to explain what you feel is going on. Provide some examples that you felt are abuse and that to you those are absolutely unacceptable. I have no idea if you can do something about this legally. You are a pregnant woman and im quite sure there is some organisation devoted to this. Take it easy.