What Causes Positive Drug Test Results For Meth While On Treatment For Arthritis?

Hi, I recently had to take a post accident drug test for work and it came up positive for amphetamine and meth amphetamines but I don t do meth or crystal meth of any kind. I do however, take a few prescription medications and do take quite a few otc meds. could you tell me, after seeing a list of them, if they could cause this result please. my job is on the line because of these results and I don t know how to prove my innocence. Thank you, Samantha levothyroxin 100mcg x 1 daily alprazolam 1mg x 1 every 4-6 hrs as needed modalert 200mg x 1 daily ib profen 200mg x 3 twice a day for arthritis symptoms psudoephedrine (2 pills per dose) x 2-3 times a day as needed ranitadine 75mg x as needed for heartburn nyquil/dayquil (only recently for common cold symptoms) vitamins b,c, and d