Saying 'Allah and the Messenger are free of me on the Last Day if I did such-and-such'

Q 3: I used to be a smoker, but twenty years ago one of my friends paid me a visit at night. After a while, the Adhan (call to Prayer) for `Isha' (Night) Prayer was proclaimed and I told him to go to the Masjid (mosque) to offer Salah (Prayer) in congregation. However, he told me that the time due for offering `Isha' Prayer is long and that he would offer it when he returned home. I replied, "You are a kind and virtuous man, but you do not observe congregational Salah." He said, "Although (Part No. 23; Page No. 53) you observe congregational Salah, you have a defect, which is smoking and smoking is Haram (prohibited) because it is a bad practice." I told him, "Why do we not agree that I quit smoking and you observe congregational Salah?" He said, "I doubt that you will be able to fulfill your promise, but I agree." i, thus, took an oath, saying: "Allah and the Messenger are free of me on the Last Day if I smoke a cigarette, a pipe, or a hookah." All praise is due to Allah that I have quit smoking. But after ten years of quitting it, I smoked for one or two days and then quit again. I have been meeting some of my friends who smoke hookah for about five years, and I join them in smoking once a year.My question is: Will Allah (Glorified and Exalted be He) and His Messenger disown me on the Day of Resurrection and will my good deeds not be accepted, Allah forbid? Is what I said considered an oath? If so, what should I do? Should I offer a Kaffarah (expiation) for each one of the five times in which I smoked tobacco or hookah after quitting smoking for twenty years? Please advise and guide me about what I should do to end the obsession I am going through. May Allah reward you with Jannah (Paradise) and its blessings and gather us all into it.