Well done you ! Keep it up, it's worth it.
I gave up finally when I was 30, I'd had a couple of goes at it, but I knew I could ride faster if I quit and that was a really powerful motivator.
I didn't use nicotine patches - not sure if they had been invented then - but I did read Alan Carr's book, and I had acupuncture which involved a tiny drawing-pin being put in my ear, not my actual ear canal but the cartiledge bit. Every time I fancied a fag I was to wiggle this pin and take a deep breath. Weird? Yup, but it bloody well worked.
I did put on a bit of weight, but that soon went, and I coughed for a bit, but that stopped too. Apparently we have hundreds of villii (tiny tentacles) in our windpipe/lungs which filter out crap. Smoking, I was told, paralyses them thus when you stop smoking they come back to life and desperately (in sort of reverse peristalsis I guess) push all the rubbish out.