The mark of a good instructor is one that can tailor his teaching to each individual student. It is obvious that he is more comfortable flying the plane at high speed but to be honest he is doing you a diservice by not focusing on the slow speed handling of your plane. it takes much more skill to learn how to handle the plane at low altitude and airspeeds than it does to be hauling butt around the field. Telll your instructor that you are uncorfortable ad if he doeen't tailor his methods to your abilities send him packing and find someone else. It is obvious that you are not enjoying the flights as much as you could and that is going to push you out of the hobby. Find someone who will help you learn in a more comfortable fashion and you will have much more fun!