Let me take everything you said about trying to quit smoking, and it can be directly applied to me trying to quit drinking...
I drank so much and so recklessly that pretty much every time I would blackout, no exceptions. Some people can enjoy alcohol responsibly and stop when they want to, other people, such as myself, go until there is no liquor left or we just plain pass out. I began losing money to drinking, my grades slipped horrendously, my health started to decline (as well as my hygiene), my resting heart rate was always above 100, I developed panic attacks and anxiety if I hadn't had a drink in 24~ hours, I couldn't even go outside or leave my room the anxiety got so bad sometimes. It got to the point where my relationships with my friends, family and SO were severely strained. So much so, that many people who are near and dear to me were threatening to cut me out of their life for good if I didn't stop drinking all together.
Anyways, alcoholism rant over, I eventually was able to quit after multiple attempts (I honestly couldn't tell you because alcohol destroyed my memory quite a bit during that time frame). But, I guess what I'm trying to say, man, is that I know how hard it can be to quit a substance. The hellish withdrawals, agitation, cold sweats and overall depression are things I wouldn't wish on my worst enemy. If you are truly serious about quitting, then don't try to do it alone! I wouldn't have been able to quit alcohol without the support of some great people in my life, hard work, and extensive substance counseling therapy. My piece of advice to you (if you're looking for some, that is) is to seek outside guidance to help you quit, because the withdrawals and depression can get very scary very quickly if you try to quit alone. You might always have an itch to smoke, but that is normal, and you will learn how to control those urges once the initial withdrawal effects are replaced with mental rather than physical cravings. Best of luck to you in your journey to quit!
Also, I'd like to add that I'm not advocating that anyone abstain 100% from any drugs or alcohol, I'm very pro-drug and think that (most) drugs can have many hidden benefits if used wisely and in moderation. However, I think that when a substance begins to greatly diminish a person's overall life quality, rather than enhance it, it might be time for that person reevaluate whether or not their substance(s) of choice is a positive or a negative influence on their overall quality of life. It is then up to that person to decide if their substance(s) of choice is/are actually something that they can tolerate the continued use of. Some people can be taught how to use in moderation and can be perfectly content and healthy, other people have to quit entirely to get control over their addiction(s).