I have been on pain management for 10 yearsand now I am completely off why do I feel so anxious

That is a very long time to be on opiod therapy so to have it removed without the help of a pharmacology assessment - meaning seeing if you need some temporary medications to help you through the process - is a bit surprising to me.  So i would feel it "very proper" to raise the issue, the difficulty you have and to request that maybe you get an assessment and therapy plan devised to help with the anxiety and sleep issues.  It sounds like additionally seeking the help of a therapist so you can avoid significant medications in lieu of therapy to work on the anxiety issues might also be a good move to make.