Did I Pass?

I took this drug test for this job......and I used someone else's piss that was clean. But here is the problem that has me worried.....When I went to the bathroom and took the bottle of clean piss out, it wasn't enough for what he told me to fill up so I had to piss a very small amount in there to make the amount sufficient enough. I already know I am dirty with THC. But will my small amount of piss trigger positive for THC or will the clean piss dominate? I am so worried.