Quitting for good and improving my lung function for life

My father had been a smoker since his teens, and I always hated the cigarette smell and the thought of smoking alone was disgusting, I remember watching the grim reaper ads as a child and thought I would never smoke. My first cigareet was at a sleepover, my friends mother let us sleep in the tent and she actually let us smoke and bought them too, we were only 14 at the time. I only did it to be cool and because everybody else did it. My friend smother had a lollyrun and at least 14 kids from school would do it after school , make a bit of money and she would also let the kids smoke and she would buy for them aswell. I only did it top be with the in crowd I guess, but it diidn't last long. I got my first job at 18 in a local hospital doing kitchen work, there I met a worker who had strongly encouraged me to smoke. I should have said no, but I wanted to feel a sense of belonging as there were quite a few smokers, during my time of employment I suffered many bouts of pnuemonia and hospitalised each time.  I can only certainly say it was from smoking even though doctors didnt tell me exactly the cause  but of course I know it was from smoking as I would smoke quite alot nearly 50 a day at some times. I had also been trying to fall pregnant and that took many years ten in total. When I learned I was pregnant I left my GP's office, cleaned out my handbag, threw anything associated with smoking in the bin and went home happy, knowing that I had to quit no matter what. It was very successful, I did one day have an urge to try  to have a cigarette but I lit it, tried to draw it back but just could'nt stomach the idea knowing I would harm my unborn child, so that was the start of quitting and it felt great, my mind was only ever occupied with my baby and reading. I decided to breastfeed and because of that too, my quitting took in total 2 1/2 years in total. During the prgnancy I took up swimming everyday, sometimes two times a day , doing cardio workouts with dvds at home and walking so I started to feel great. However things turned bad as I took up smoking when baby was 8 or so months. My baby is now 16 months so I have now been smoking for 8 months as my relationship was falling apart my partner could not handle the responsibilities of a baby, even thopugh he strongly wanted to be a father. I find at this current time, I am smoking as I get stressed from my relationship status, I am currently studying doing my bachelor degree in health promotion and even thats not enough to tell me to stop. I know if I was pregnant I would immediately stop, I have even tried telling myself I am pregnant but its not enough, with an empty tummy. I don't smoke around my child and not inside the house or car as i know I can't even breathe properly in small confined spaces, However I have cut down tremendously only buying a pack of 20 instead of 30 or 50 and 20 can last me up to 3 days, so I am prepared to keep cutting down, but cold turkey, although I've done it cold turkey it still is a little hard and working in health promotion is also wrong for me to be smoking aswell. I truely hope I can give up this time again as I felt fantastic when I didnt smoke. I also plan on buyng a POWERBREATHE breathing trainer so I know I am looking after my lungs and of course getting back into swimming