I also quit using Chantix. That was about 5 years ago. I have to say that I have never had such bad side effects from a medication then Chantix. It was brutal. Literally I would take the morning pill right when I walked out of my house for work. Less then 5 min later, before I could grab a coffee and a doughnut, I had the worst nausea in my life. It was like clockwork every day, pop the pill, 5 min later I'm green.
Then the nightmares and dreams started. Some real messed up shit.
It did work for me I quit for almost 2 years, then started back up again about 3 years ago.
I am going cold turkey now. This is my second day with no cigs. I am chewing trident like its going out of style. The 1st day was the worst, today is still bad, but much better then yesterday. Day 3 will be better, and so on and so fourth.