I can't help with a doctor in Tuscon, but as far as the withdrawal goes, you are going to have a rough few days I think. 8-10 percocet a day is a little high as far as short acting meds go. Is that how many were prescribed a day for you?
How long have you been taking them that way?
I would get some immodium for the diarrehea that you will probably have, some gatorade type drink, some tylenol pm to help with the lack of sleeping and other than that, you are going to have to ride it out. The good news is that you will be mostly over the rough part in 3-5 days.
You won't die from it, but it is not pleasant to have to go through.
If you tested positive initially, why did the doctor continue to prescribe to you? I am a bit unclear about a timeline for this. Did you continue to smoke marijuana while seeing the PM? Is that why he cut you off?
I know that many PM's now have taken a stance that they will not taper a person, once they are cut off since withdrawal is not life threatening in most circumstances.
Ultram and Ultracet are not narcotics but have been known to cause withdrawal once they are stopped since they work very much like opiate pain meds . However, I would not take them since you are trying to get into a new PM.
As far as the PM you saw today, he may have a different view of pain meds, many have gone into doing injections rather than pain meds. Also , many more PM's are not prescribing pain meds until you are an established patient, which means that you have been seen there more than once.
I wish you luck in finding a new doctor, but my best advice would be not to take anything not prescribed for you at this point and to stay away from the marijuana.