I had one 12oz beer at 4:30 Saturday. I am 5'6" 165lbs I could get tested Tuesday morning. Do you think I will fail?

Yes.

It doesn't matter what the test results are. If you said you wouldn't use alcohol, you've blown it.

If you didn't make that promise, others (including courts and companies) are going to think what they want to think.

Can you get back on the wagon? Yes.

Can you STAY on the wagon? I don't know you, but multitudes have, even after a couple of falls.

From two gallons of rum on my twenty-first birthday, I have cut back to a couple of egg-nogs on Yuletide Eve. It can be done.