Stop everything that you're doing right now. You're going to be fine. Urine screens are by far the most over rated things ever. In order to test positive 30 days after smoking, you would have had to have been smoking a shit ton of weed. Just to be on the safe side, on the morning of your test, start drinking water and just keep on drinking until you go pee, and then keep on drinking until you have to pee again. You want your pee to be as clear as possible. Good luck, but you won't need it. You'll definitely be absolutely fine.