Talk to your ob-gyn, it will NOT be the first time they have heard this from a pregnant woman. I would not recommend cold turkey either, but do recommend you try acupuncture during the time of weaning off the drugs, and afterward for pain management. It worked wonders for a chronic shoulder problem of mine that hurt me all the time.
I wouldn't go cold turkey cause thats a lot of stresson yer body n stress can cause a miscarriage...I would definitely talk to yer ob and see what they suggest