studying for thermo

can't believe i'm studying at this hour. the haze is irritating my throat and i can't slp. decided to make full use of my time to look through thermo notes and tuts. i guess it'll make a big difference as compared to not looking through them at all. why must we have all these tests and CAs. . it's supposedly there to help us pull up our grades but wad if i do badly for it and in the end it pulls down my grades?