I am on probation in MD and had to take prescribed drugs...Any Advice?

I just had emergency surgery yesterday and I was prescribed narcotic medication for my pain. I have my prescription, discharge papers and my actual medication in the bottle to take to my probation officer but I am afraid that this will not be enough to prove that I had to take this medication. I am going to take a drug test and I am sure it will come up as positive because of the medicine..has anyone been in this situation before? I have all necessary paperwork to prove that I was prescribed this medicine by my doctor.