im sorry you are having so much stress with this teacher. she doesnt sound like a competent teacher. some teachers have issues of their own and sometimes they let them out on others. she behaved very unprofessionaly in my view. its not constructive at all for her to say things like that in front of the class. as you said, you could ask to be assigned to a new teacher. or you could try to focus on your goals and try to not let her get to you so much. you know best what your strngths and weeknesses are. dont get discouraged by a teacher who doesnt even know you well enough to make judgments like that. wishing uou all the best!