I HATE MYSELF!!!

I am so mad at myself. When I was having exam, I can't remember what I had studied. I prepared for the exam since few days ago. I memorized everything but when I was writing for the exam I can't remember anything. I really don't know what myself is doing. I wish to have a better grade but now, I think I won't have good result for this subject. Everything is ruin! I hate myself for being so useless. I hate my stupid brain. I hate studying and memorizing. HATE IT!