My dad just passed away after suffering a long illness and I took an occasional alprazolam (over a week ago) to help me sleep. I just took a drug test for pre-employment. The drug test showed positive for THC. I do not use Marijuana. I am on Amoxicillan, Prednisone, and Sudaphed for a severe sinus infection. I take a men's (over50) multivitamin, bee pollen, potassium, b-12, also percogesic for occasional arthritis pain. Can any of these cause the false positive?