What Can Cause A False Positive For Methamphetamine? At The

What can cause a false positive for methamphetamine? At the time i think all the medicine i was taking was depakote, trazodone as an overdose, that day i didnt take benadryl, vitamin c and fish oil,ibprophen and albuterol but either take normally as needed or every day
. I had them retest me taking the same medicine and it came out negative.My biggest concern is i recently moved into a house recently where the people that use to live here smoked it and made the meth iin the house and the shed in my yard. Can that have anything to do with the false positive. Thank you.