I Have Been Taking 25mg Of Promethazine (along With Tizanidine)

I have been taking 25mg of promethazine (along with tizanidine) 1-3 times per day for the past few years for different issues (fibromyalgia, migraine, insomnia). After fighting a migraine for more than a week and taking the promethazine and tizanidine two to three times per day I'm noticing withdrawal symptoms! :( I had no idea promethazine could cause these symptoms and never would have started taking it in the first place had I know. My question is what is the best way to taper down?