First time marijuana smoker question?

Ok I smoked yesterday for the first time, EVER. I took about 5 or 6 hits last night, and we got some strong dank too so I got pretty high. Anyways, I have an appointment with my allergist in a week and I want to know if I would p a drug test (not urine test they never make me do that). I'm 140 pounds, skinny & muscular with a very fast metabolism. They always make me blow into this "puffer" connected to the computer to measure how strong my lungs are (I have mild excercise induced asthma). I'm not sure if they look for anything in your lungs like drugs, but I just want to be sure. I've heard if you drink lots of water & take a vitamin everyday then you'll be clean in 3 days, is that true?