Before surgery I had many difficulties with nausea and meds. I would take them, then four hours later throw up. I found a combination of constipation and caffiene were the problems. I went from Vicodin, to Lortabs, to Percocets, to Bextra, to something else. After I got my bms under control I no longer got sick(I also started caff. free drinks). Now I will if I accidently take a dosage that is simply too high. We can get sick if we don't need the amount of meds given. Maybe you need a lesser dosage pain med like Vicodin fives or percocet fives. Something not so strong. Darvocet is pretty strong. I can't take percocet tens anymore, I am now on seven point fives. If you are weaning off meds try a not so strong dose.
Wow, you have lost a lot of weight, in a way, I envy you. I gained five pounds.