It sounds like you are putting too much stress on yourself and you put a lot of weight on what your professor thinks of you. Of course you want a good relationship with your professor, and you want him to think well of you. But he doesn’t have to think you are perfect, and it’s OK to take a while to understand a concept. Sometimes you might have to tell him that you are having a difficult time understanding but you’ll address that at the tutoring session. That way he can get on with moving the class along for others. I do think that @bopper’s comment about going to the counseling center is a good idea. During the course of your life you will have to deal with all sorts of people who will be in positions of authority (like your future boss), and the counseling center can help you learn different ways of communicating with them and managing expectations. You are so young now, that you haven’t learned all the skills you will need in life dealing with others, and working on these skills will help you significantly in all stages of your life. It’s a great investment of your time for your future.