I'm sorry you are having problems with this particular teacher. Given the circumstances, I would try to "block" him out and come up with your own plan, write it out and then work it. You can only do what you can do and you are doing it for yourself, not him; doesn't matter if you "fail" or not in his world; your education is for yourself and what you want/need to learn to help you. Come up with a reply to his comment that he can't argue with, such as "Yes, sir, thank you sir for your time" and then go back to whatever it is you are working on. Experiment with various replies and see which he "accepts" and leaves you alone more after and which cause him to try to get a different response from you. He could seriously think he's helping by noting when you're not working or he could just get his jollies when you jump guiltily or resentfully, etc. He might not like it that you are confident and moving at your own pace, doing your own thing. But that's life; he won't be your head teacher forever! You are your ultimate head teacher.