Your best chance to not only quit smoking, but also, to "stay quit", is right now. Do not put it off until later in the term. You know how stress builds towards mid-term and certainly as final exam time approaches. That is not the time to try to quit smoking! Quitting smoking is stressful enough. You just don't need the added stress of approaching exams to interfere with your beating your addiction to nicotine.
"Addiction?" Yes, addiction. Most people regard smoking as a "bad habit", but it is much worse than that. Why do you think it is so hard to quit? Surely you have noticed your withdrawal symptoms when you haven't had a cigarette. It is an addiction, and a support group consisting of smokers helping smokers quit and stay quit can be critically important to help YOU.
more later...