Ugh, what you are going through sounds painful and I've been there so I can totally relate. The first thing I would ask (and I apologize but I don't have the history of your other thread) is what is your experience like when you learn things quickly i.e., certain subject matters that just come easily or problems posed with words versus numbers? Figuring out what comes easily may help you come up with a new strategy for your studying OR may suggest that whatever you are currently studying isn't for you.
I am an intuitive learner in a technical field. Thus I'll be lost for a while sometimes and then get a huge download of information into my brain with an "Aha!". Does your knowledge come in bursts?
Can you find another book on the subject that is easier to understand? Sometimes hearing the same thing in different ways helps a lot.
When you get stressed and angry, take a break and, if possible, move your body until you feel better. Try to observe what is happening dispassionately instead of judging yourself, if you can.
Good luck!
