Wow . . . all I can say is keep trying, it is so worth it . . . and it does get easier as time goes on . . .
I stopped a 'pack and a half a day' smoking habit cold-turkey about 21 years ago. It was not easy, I thought I was going to go absolutely insane for the first few weeks. I had to take sleeping pills because I couldn't sleep. I think it is the memory of that period of time that kept me from ever having another cigarette. I was sure if I had one, I'd be right back where I started from in no time. For the first few months, I even avoided all social occasions that usually led to smoking, like going out for drinks or even going out for dinner.
It took years (many years), but I finally no longer have any smoking cravings. Darn it all, I wish I could control my bad eating habits the same way . . . i.e., by never having another bite of food . . .
I'm the exact opposite of Penney . . . quitting smoking was easier than quitting over-eating.