hey, i'm in nursing school too...thank god we don't have to drop lol.
anyways, not smoking is obviously #1, so good call on that. try taking at home tests (go to rite aid or any pharmacy or walmart, etc) and see if you fail those. if you can pass those, you'll probably pass the lab ones.
how heavy of a smoker were you? like how much a day/quality of weed/how long you've smoked...these will all play a big factor
if you still drop dirty on the home tests and are getting desperate, try ureasample.com. i used it to pass a job test. they sent my sample to one of the biggest testing companies around and i had no problems.
good luck fellow nurse
I figure if I study high, take the test high, get high scores!