Most Helpful Girl
You're not going to get get back right away, if you do. I don't want to hurt your feelings or make you sad, but that is a big deal. You grabbed her face and put everything on a lie. The ONLY way you will get her back is through actions. She will have to see, in her own time, that you are sincerely making a change. I wouldn't rush her or you may push her too far away
Most Helpful Guy
"we had plans for getting married and live our lives with each other by each others side"
After EIGHT months? Was this by any chance your first relationship? Because usually guys are only that dumb when it's their first time.
"we have a love so rare some people may never experience it."
Again, something usually only said and believed by kids in the first flush.
A girl that walks away because you're smoking, isn't someone mature enough to make a life long commitment. You're both obviously just kids, who still believe that issues are black and white and there's no room for nuance or overlooking trivial issues in a relationship.
If I was being harsh, I'd say grow up. But let me just say this instead - she's not the love of your life. Most grown up guys have gone through exactly what you're going through, and we look back now and laugh at our idiot younger selves.
It will pass. There's other girls out there. Even if you can't believe that right now, it's still true.