since i was honest about not being able to pass and admitted it wouldnt that be a reason enough to check me or give them suspision that i might try to cheat it when i do try?
For starters, you were being honest to your prospecting employer, not a specimen collector, isnt that correct?

You definitely are being paranoid. Relax. As long as you dont show up at the testing facility with "cheating contraband" dangling from your shirt pocket, or otherwise exhibit any behavior that indicates intent to tamper, then you wont be suspected of tampering.

And when submitting your sub sample, it is important that you make sure the temp is in the proper range of 90-100F. If the sample is not within the proper temp range, then the collector will order an immediate re-submit and under direct observation (the observer must be the same gender as the donor, as per DHHS regulations - no exceptions!). The collector will then process and send off both samples and indicate on the test forms "Remarks" space that a direct observation collection had taken place and the reason(s) why.

When subbing, it is advisable to do "practice drills" at home using warmed water in place of urine. Practice with maintaining temp, pouring, etc.

The key to pulling off a successful sub is PRACTICE.