I didn't have too tough of a time quitting either. For me, it was a kind of "accidental" quitting. When I first stopped, I still intended to go back eventually. That made it easy for me---I wasn't quitting forever, but only while I took some classes at my local community college. In between semesters I'd go back, I figured. Only I never did. Here I am, over five years later, still completely sober.
Oh, I have occasional thoughts about going back. Just these past couple of weeks I toyed with the idea. But it's just not worth it. Not by a long shot. So it's not really a serious temptation, because I realize how dangerous it is for me.
Obviously, my experience differs from yours in that my realization was more gradual, whereas yours appears to have come on rather suddenly. But once you have that realization, it's not terribly difficult to stay away from drugs and alcohol. Or so it seems to me.