We can't really delve into the subject of Urinalysis as it's against the rules and trying to speculate on why you came up dirty is just that... pure speculation.
I'd guess that one of the substances you used was adulterated or it was a false positive that needs GCMS confirmation, but again this is outside the scope of what we can discuss.
Hope it works out and you get to the bottom of what's going on but I have to close this.