Well done so far Dave, I hope you stick with it.
I was a heavy smoker before I became a jw, and had a lot of trouble quitting. To be honest, I never totally quit, I had an odd cigarrette during my years as a jw, and always felt terribly guilty afterwards and resolved not to do it again. When I da'd, I foolishly got into the habit regularly again, and within a few months was smoking 20 - 30 a day. I tried to quit when Trev quit, but whereas he has managed so far, I lasted just under 3 weeks, and though I've cut down a bit, I still smoke at least 15 a day, sometimes more if we go out.
I'd like to stop eventually, but I think I'm a good way off summoning up the strength to make another attempt yet.