What Causes False Positive Result For Methamphetamine And Oxycodone While On Morphine?

Onmy last drug test I turned up dirty for meth, the street drug. and oxycodone. all I take is 3 thirty ml morphine 3 times a day . and propananol for high blood pressure. I did not take any of these drugs they said that turned up in my drug test. I hate illisatedrugs. I have never turned up dirty on any drug test ever. what do I do. they are going to kick me out of pain management. and I don't want my name smeared. any ideas.