No no, STOp drinking water now. Sounds like you are giving yourself water intoxication. It can deadly and vomiting, headaches, and dizziness and signs of it, so stop drinking water now.

You gave yourself only 36hours of no smoking, and only 4 hours to prepare. You won't pass the test unless you use a clean urine sample. You should have started drinking water and such 2 days ahead or so before the test.

4 hours isn't enough time to dilute your system and get it cleaned, so stop drinking all that liquid before your brain swells from too much water intake.