I'm an ex-smoker. Quit smoking when I quit drinking, but I was desperate. Drove people a bit nuts for a while, but I was neurotic, and that came with the territory. Just went to a lot of meetings and became willing to go to any lengths. These days I would try Nicotine Anonymous.
It's a big blow to the ego to feel nuts, but you just walk through it one day at a time, learn about it, learn new behaviors. You've been sober for a while, you know the drill. Doesn't mean it's any easier, but you can do it--with the -proviso that sobriety comes first.
Good luck!