I'm A Chronic Pain Patient Suffering From Reflex Sympathetic Dystrophy

I'm a chronic pain patient suffering from Reflex sympathetic dystrophy for the last 8 years and have been taking oxycodone , gabapentin, cymbalta, aspirin, aderol, muscle relaxers and sometimes lyrica.
I tested positive for cocaine in my monthly urine screen , is there any medications I currently take or possible other over the counter medications that could show a false positive. My blood test came out negative 2days later so that's left me very confused.