How to breathe if you are a smoker

Hi,
I faced a problem. I started learning yoga several weeks ago to reach a better physical form and to improve my stress management, but my body isn't prepared for such stress and it' s hard for me to create a new lifestyle. I have been smoking for several years and now I feel how it affect my health. I am shocked. I tried to quit cold turkey but I broked down, I need some alternative ways. I heard a lot about nicotine gums and vaping, found several sites where people trying to quit and creating some communities to make quitting easier (like this http://quitsmokingcommunity.org/) but I can't believe some random info and don't wanna be advertised on the internet. So if you know some alternative interesting ways to quit and become a better version of myself, please, give me know. Thank you!