I was called into the doctors office because of a failed drug test and was told that he would no longer prescribe me any pain medication. I left there without a 30 day supply while I was to seek a new doctor
No, the doctor is not legally required to provide 30 days of meds or taper you.
When you are dismissed for violating the pain contract, they typically send a letter telling you you are dismissed and to seek further care with another provider.