Used expired synthetic urine. Will I pass??

So this is probably the scariest moment of my life so far since there is so much riding on it. I rarely smoke anymore but happened to smoke ONCE two days before this incident. I work at an ER and was pulled aside by my boss early Friday morning asking me to take a drug screen. So anyway, my boss walks me to the lab and I happen to have a bottle of magnum synthetic urine with the code S3 on the bottom in my pocket just bc I knew I wasn't clean for MJ. My boss assures me if I pass everything is fine but if not I'm reported to the board and there are serious life changing implications. Anyway, after stalling for about an hour with it under my arm, I subbed and everything checked out. The kicker is this: that bottle of synthetic was 3-4years old!! And I read on ncsbn website that if a sample comes back adiltered or subbed, you fail automatically. My question is: what happens after the shelf life ends?? How long does it take time to actually affect ph and/or creatinine to the point where the sample is no longer good?? What are the chances I'm ok here?? I tried calling their 24 hr customer service today and got nothing. Is there a logical way to explain this away if they DO happen to question me about PH or Creatinine levels?? The test I took was through quest diag. Sap 8-50 w/nit. Since my career hangs in the balance here I. Haven't been able to sleep. This happened Friday at 7am and now it's Tuesday at 9am and still no word. Is that a bad sign? I have been really losing sleep over this and am a nervous wreck. I swear if I get out of this ok, I will never mess around with anything ever again!! Hope u guys can help!