I am 5'9" and 140 lbs...I passed a drug test on 07/18/11 and I smoked last weekend 1 (cig), then one (cig) last night. I found out I have a test on monday. I have purchased herbal clean Qcarbo and was told that it would completely clean my system and that I should drink it sunday. I have never used it before...Does it work and if so when should I drink it? I drink about 1 gallon of water per day...should I drink more water also...Someone please help me I can't fail this test!