I took 3 hits of a blunt of weed last night, i have a drug test tuesday (in two days) will i likely pass?

it is a urine drug test. i weigh 106 pounds; i heard the less you weigh the faster it flushes out of your system. also, i heard drinking alot of water helps, along with trying to pee alot, and sweat. if theres a chance i wont pass, any suggestions on how to sneak a clean friends urine in with me, and how to hide it to be the right temp.?