Welcome Swash, congrats on your choice!
First off, let's change "pretty sure I can quit" to "I have made the decision, I am quit". Post roll call early everday, keep that promise for 24 hours, then repeat. Simple and effective. Will it be hard? Hell yes. Mostly likely the hardest thing you will ever do. I can promise you it will be worth the effort.
As far a the pissing matches, take what you need, leave the rest. These little spats are a way of channeling the rage brought on by quitting. Better to do that here than at home a the wife and kids.
Remember how shitty you feel right now, remember it well. If you stick with us you will never have to feel that way ever again.
Most of all, shout if you need anything.