How should I study better, I have a testing problem?

I have this testing problem. I will know ALL the answers every single one, but when I get to the test, I dont know any of them. Its like the teachers are trying to give me college tests, instead of high school exams. I have always been like this, but now in high school grades count. All my homework grades are pasingl, but the test scores are bringing down my grade!! How can I stop this?? its like..if I study too much...I'll forget...or freak during the test...and if I don't study...I dont know any of it. its like...either I know it or I dont. im screwed...how am I supposed to pass high school?

Don't fret! My grades sucked and I still got into wake forest. The key is, don't study too much. When you go to take the test, the chemicals in yoour brain make you go wacko. I know that bc now I'm a doctor. Stress-flight sucks bc you get a psyched out. Look. Study 2 days before don't worry about it the night before.