Gosh don't be so hard on yourself, is that an 80/100,honestly if so i think that is an awesome grade,one can only try and do their best,your teachers sound a lot like my daughters too, she is always complaining they don't actually teach properly, and it is so annoying, you expect them to do their job properly, she is in high school and is 16,doing her real important exams in about two weeks time,just keep on giving it your best shot and if you know you can do better, you will next time i am sure. cheers