Smoking... My last true battle!

So I lost 160lbs., I gave up drinking and became a marathon runner. You would think that along the way I would have stopped smoking. You would think the runner's high would have been enough. That my world had changed so much that I would no longer need to suck on the cancer sticks to get through the day. Truth is it never crossed my mind to quit. There has never been a moment when I said to myself "You know what.. I think I should quit this too!" I've changed my whole life and yet the worst habit I have I can't get rid of. There comes a moment when you realize you need to change, just like my weight and my drinking.. I need to quit smoking.
I've been smoking since I was about 12. In my area it was easy to get cigarettes, even at 12. I thought it was cool and was being a dumb rebellious teenager. Truth is I wasn't that addicted during my youth. It helped somewhat ease the pain of a rough teenage depression. Truth is drinking helped a lot more.  Once I hit my twenties is when my smoking took off. I lived in the south for a year and that's when it became about 2 1/2 packs per day. I was teaching dance at a horrible job and everyone smoked. I would go out behind the building and smoke between each class. It became so bad it was hard to teach. That's when smoking became an outlet becasue I realized my dream job was a nightmare.
After that awful experience I decided to go back to school. I got my bachelor's in exercise physiology because I liked science and dance. During school my smoking went up to about 3 packs per day. Pulling all nighters and chain smoking became the norm. My professors would see me outside and just laugh. I guess my grades were good enough for them to overlook the obvious. After I graduated I got the job I currently have now and that helped me cut back. You can only smoke so many times per day. Unfortunately this was the time I gave up dancing due to my inability to deal with the pressure and my weight exploded. I was eating so much and became severely depressed. Even though my smoking had cut back my food and alcohol Jones had become unmanageable. Then I went to the doctors, get rejected blah blah blah....
During my transformation I held on to the cigarettes with the mantra of you can only do so much. Well now I really have no more excuses and surprisingly shortness of breath is never really the problem with my running. When people see me at the finish line they are always surprised to see me smoking and make some sort of funny joke. Today on my walk to work a runner saw me smoking and gave me this awful, judgemental look. first I was thinking that's so rude. Then I realized this guy is right! What the hell is my problem. I can run marathons, lose a ton of weight without surgery and yet I'm still chained to the cigarettes. I don't know if I'm ready to quit just yet but this morning was a wake up call that the time is coming. It scares the shit out of me. How do you quit your best friend? with 4 days until my half, it won't be tomorrow, but maybe soon. Less than 3 months to Paris and I know at least I won't be judged there, but maybe I should.