Sounds like you might pass to me.

Three weeks is a decent amount of time, your not very big, and your in school so I assume your young with a good metabolism. Try a home test though, you can buy one at a pharmacy for less than $20.
tsmith3402 Reviewed by tsmith3402 on . Will I pass my Drug test. Tomorrow I have to take a drug test for school. I havent smoked in 3 weeks and before that i didnt smoke for a week, but before then i smoked almost every day for a couple of months. I am 5'9 and I weigh 140. Rating: 5