@The Artisan: There is no one Islam, find the path that is suitable to you, the one that convinces you. It doesn't have to be an established madhab or whatever fancy word people want to use.
The first step for positive change is acceptance. You have to accept who you are, your flaws, your past mistakes, your sins but also your achievements, your qualities and your good deeds. Accept that we all strive to be better and that in itself is really hard work. It takes a lot of time, it takes patience and you won't necessarily see the results right away but that is how you know you are on a path that's worth taking.
As far as depression and smoking goes, I firmly believe that this is something you have to discuss with a doctor that knows the particular interactions between the two. I don't know if you have already done that, but in my opinion, it should be at the top of the list of your priorities. Make sure to get a second and third opinion too as mental health is a very complicated matter. If doctors tell you that smoking is one of the reasons you are having these difficulties, then you will have to work on that, if not, well, then you work on whatever other issues you are able to identify and ignore people telling you otherwise. This doesn't have to be about religion.
Remember that Islam is not only about serving Allah but I'd argue, most importantly, about bringing happiness to you and those around you, and that is in my opinion the ultimate form of serving God. You seem to be living through an intense internal struggle, my advice to you would be to identify the contradictions that are leading to this situation and think about them in a rational manner. Remember that rulings in Islam (or any law really) exist for a reason, and that the reason of the ruling is more important than the ruling. If the reason does not apply in a certain context, then the ruling too should not. That is my opinion on the matter.
Identify your core belief values (these vary from one person to another), discuss those with like-minded individuals that you can trust. Find out how your reading of Islam is compatible or not with those values and go from there.
The internal struggle between who we are and who we want to be is something we all suffer from at some point in our lives. When it comes to religion, I believe it is important that this struggle be justified by rational and convincing motivations, not just blind following of society's established rules. That is where you will get the willpower, energy and commitment to improve as a human being.
One thing I will tell you, if the main reason why you want to stop smoking is religious, then you are looking at this from the wrong angle. You should be the one defining what is sacrilegious or blasphemous. We live in a world where we are highly educated compared to people of our age even 50 years ago, you have the means of deciding for yourself. For example, let us suppose that for you, your family is the top priority and that they are pretty opposed to smoking in general. Seeing as Eid day is one where families tend to gather and spend the day together, it could be considered blasphemous for you to smoke during that day - even though you would be fine with smoking any other day - because it could negatively affect your family's state of mind, in this particular case, it is worth making the slight abstinence effort. So in a way, the question you should be asking is not "is smoking blasphemous?" but "are the consequences of smoking fundamentally negative in this particular context?".
I guess it's time for me to tell you of an anecdote about how giving up smoking can take quite a bit of commitment sometimes, I have a friend that also used to be my roommate. He was going through a really rough time in his life and was clearly depressed. He would go on these weed smoking binges for days and days and it would clearly affect his state of mind. This is a guy that was very cool usually that with time, turned into a depressive, extremely paranoid person. One day, I came back home to find that he had removed all the light bulbs from the apartment and was combing through them for signs of hidden mics or cameras because he thought he was being watched. It was quite the extreme case. It took him going back to live with his family and seeing a psychologist for a few months for him to recover. That is how he was able to stop smoking, he would have never been able to do it alone. And like I said, this is normally a very nice, educated guy and yes, a muslim. More importantly, he decided to stop smoking because he identified the negative consequences and had the proper support to do it.
I know nothing about your case, it could very well be that smoking actually helps you more than it hurts you or your entourage, that is why I encourage you once again to first see a doctor, and secondly do the work I talked about in the previous paragraphs.
Hope this helps.
