From a former smoker....Just keep trying. It took me 1 year after being diagnosed with COPD (emphazema) to be able to quit.keep going back to your doctor for different ways to assist your quitting. Their are alot of tools and drugs you can try.
I tried everything from hyptnosis, cold turkey (usually would last just a few hours), prescription drugs, over the counter remedies, etc. Finally 2 1/2 years ago, instead of going on vacation I stayed home for a week. I quit that Monday morning on the patch ( which I tried many times before). During that first afternoon I had to do something or I was gonna fail once again. The best thing I ever did was grab a putty knife and start peeling wall paper. I now call it "MY WALL PAPER THERAPY". It gave me something to focus on and kept my hands busy. Oh, and by the way....the best wall paper remover is 90% warm water and 10% liquid laundry softener.
If you really want to quit, you just have to keep trying to find something that works for you. Good Luck, I wish you the best.