It's difficult to stop something you are very used to do. I might be to dramatic here but in my experience of quitting some of my addictions I felt like I was letting go a part of myself, it was really hard. Luckily, I had some support from my family and friends. You can do it man. It may take some time but as long as you have the will, you will succeed in quitting your smoking addiction. Good luck and I hope you all the best!