I agree with Ex and Brian regarding transition.
My transition, due to severe reaction to high dose of Fentanyl patch, had to be abrupt, still I did not have much problems at all. As Ex said, the most importantly in this how knowledgeable your PM DR is.
I know everyone is different, but I believe you will be OK. My PM also believes in LA + BT meds. I am on Oxy as LA and Percocet as BT. I was switched couple of times; the minute my body becomes tolerant to medication and I feel more pain, my PM changes my medication and always works great.
I also do not believe in using GP or family Dr for pain management. Like my wonderful GP told me once that this is not a problem to Rx me Pain killers, but Pain mgmt is much more than just prescriptions; GP are not trained as PM Drs do.
Best of luck to you, sweet heart. Do not loose your hope, please. Tomorrow will be another day and hopefully better than today...