Well, in urinalysis, they measure THC-COOH rather than THC. THC-COOH is a cannabis metabolite, and unfortunately, it is fat soluble. This means it stays in your system for a while.
"For infrequent cannabis users, THC-COOH remains detectable in urine for several hours after one-time use; however, it’s commonly detectable on a standard urine screen for days or even weeks after past use in regular smokers."
The only thing I would recommend is drink plenty of water to dilute it. But it sounds like you've already given the sample.
If you smoke everyday, the signs aren't good. Is this a job that requires sobriety like a surgeon, or is this an Orwellian nightmare of a job?
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."