Cant sleep

I cant sleep now. Too Much Caffeine i guessed. nvm. i will study maths. this Friday got Test. I just feel Uncomfortable if u entered an exam room without knowing everything. i feel that i need to know everything b4 doing it. A test is suppose to be done without thinking. its all about executing it. thats all. means u are prepared. if i took a test having to think here and there, that's it, i will do badly for it.