Hello quinolone yellow: Not intending to add to your woes, but the other problem job-wise would be that, if you were injured on the job & had a "positive" drug test, your employer's workers' compensation carrier might well have a basis for denying payment for any associated medical claims. So, while I won't write that this was a very dumb thing to do (we all do plenty of dumb things) it could potentially have a variety of serious repercussions, as you are well aware.

I don't know how long it takes for something like that to clear your body. My suggestion is: quit the alcohol & the marijuana & perhaps see a therapist to try to resolve the guilt & anxiety you're carrying (assuming you're not already doing so.) No good will come from continuing along the path you are currently treading. As the saying goes: no matter how far you've travelled down the wrong road... turn back!