Ok, can someone please just tell me if I committed a mortal sin or not? I am getting mixed signals here and I am really confused.
As far a smoking goes, I wouldn’t focus on the mortal sin so much as I would focus on quitting. If you quit, problem solved.

The reason I say that is because it obviously bothers you, Lots of people don’t care. If it is a mortal sin, you will torture yourself with guilt, if not, you have a licence to smoke. Neither are good things.
If you want to smoke and it doesn’t bother you, smoke. If it does, that’s an indication you’d rather not. Don’t look for validation of smoking, but don’t torture yourself with guilt either. If you do, quitting will be much more difficult. It’s what I call ‘forbidden fruit syndrome.’ It’s human nature the more you are told don’t do it, the more you want to, even when you don’t. The more you think ‘don’t smoke’ the more you will want to 'cos it’s and addiction. The more you think ‘I can never smoke again’ the harder it will be. Imagine an alcoholic or drug addict approaching giving up from an, ‘I can never do this again for the rest of my life’ perspective. It would seem impossible. Sometimes the more you think ‘I can’t smoke’ the more you a cigarette.
To give up smoking, you have to feel ready to. I have a friend, God bless her, who has been a heavy smoker from a young age. Sadly, her daughter was killed in an awful accident. Now is not a good time for her. She will more than likely fail if she tries and that will put her off trying to stop. A nurse who checked her over said, ‘I know this is not a good time for you, but if you don’t stop your heading for emphysema.’ Of course she said it more diplomatically than that.
I you want to give up, do it when your ready and a step at a time. If you try to give up and fail, don’t punish yourself. OK, you failed, it doesn’t mean you can’t try another day. My husband says giving up smoking is easy, 'cos I do it all the time.

Take it a day at a time. If you go a day without smoking, it’s an achievement. If you smoke less it’s an achievement. Try not to smoke around others who don’t. If you do, this, you’re not hurting anyone else. Put yourself in situations were you can’t smoke. That breaks the habit. While smoking is an addiction, it’s also a habit and like any other habit, it helps to break the cycle. If your at home all day and can smoke anytime, that makes it harder. Some people smoke for something to do. Some people smoke because they’re stressed out, like some people eat, exercise to excess, shout, and drive badly for the same reason. Your no more guilty than any of them just because society now sees smoking as anti-social, and the other things I’ve mentioned not to the same extent. It’s become more acceptable to be obese, or a size ‘O’ than a smoker, despite the fact they can be equally as damaging.
One final note, to my knowledge the Church does not advocate smoking, but has not defined as a mortal sin.