I Have Been Going To Pain Management For About A

I have been going to pain management for about a year now. I have taken drug testing through out the year and never had an issue. Today I received a certified letter stating that my last U.A. showed that I have been taking hydrocodone..... the letter stated that the doctor would no longer see me? she gave me hydrocodone when I first started seeing her but it prevented me from sleeping so she changed my script to oxycodone. I still have a script written out to be filled on the 14th. Will I still be able to fill this script?