drug test Q

Alright, so I've been getting ready for a drug test that I need to take for the Postal Service because I will be working for them this summer. I was a regular smoker, yet I have not smoked pot for probably seven weeks, so I know that it is out of my system (I exercise regularly so my metabolism is good).

However, the other night I was riding in a car and my friend was toking...I thought it would be alright because he was trying to keep the smoke away from me, but I think I inhaled a couple wafts of smoke. When we got to where we were going, I began to feel the SLIGHTEST marijuana buzz. Now mind you, this could have easily have been all in my mind, yet I know there is a chance that I inhaled some of the reefer smoke.

So my question is, how long would it take before I can pass a drug test? I had a difficult, hour long swim practice the day after the incident and I have more swimming today so I have upped my metabolism and have been burning fat. I think it should be out of my system within two days. Is there anything else I can do? People recommend drinking lots of fluids, however pumping fluids does nothing to alter one's metabolic rate, thus the amount of THC exiting the body stays the same. I believe that fluids are only helpful immediately before the test as they can dilute your urine and thus you will score lower on a THC test.

Also, does anybody know if the Postal Service drug test would be 50 ng/mL or 15 ng/mL? My guess is it would be 50, as I am only working part time for the summer.

Thanks for all the help guys.