Omaha, I know that college was the absolute killer for me. Everything in college was a trigger for me. Walking to class, sitting in class, breaks between class, you name it, it was a trigger for me. The worst was (as stupid as this sounds) math. Yep, so I was a finance major and anytime I had to concentrate really hard on some math or finance theory crap I had to put a dip it. What sucks for me is that I went into a field after college that uses all that crap I did in school so it was very difficult for me to seperate the dip from the work I did / do all day.
My advice is that if you are going to succeed in quiting at this point in your life, you've either gotta get rid of everything in life that was a trigger or replace it with something else.
You can do it, take it one day at a time.