Dont freak out dude. I found out i had to pass a drug test the next day after smoking everyday. The night before I just took some Niacin and drank a ton of water and cranberry juice. But i suggest if u got any money that u get some kinda drink that cleans out your system. You can go to GNC but dont tell em its to pass a drug test cuz then they wont sell it to you.. (know from experience). Idk any of the names of that stuff but im sure u can look it up online.