What could cause a drug test to be positive for Dilaudid?

Not a 100% sure but the only thing I did differently than normal, and the messed up part is that they are prescribed that way is that I took 2 at one time. But I am on Oxy

30 IR every 4 to 6 as needed and 2 60 Morphine ER every 12hr and apparently I tested positive for dilaudid.

My Dr sent me a letter saying I tested positive and that he would not take care of me anymore and that I should ween my way off of the pain pills, like the pain has gone away? I so would get off of these things if I could but the pain is so intense that without the pills I don't want to live. So what the hell am I suppose to do? Blah Blah Blah... I hope this answers your question.

I believe that the morphine was the problem because I normally take 1 every 6 hrs.