Quit,
I remember how it felt back on Day 2. First and foremost you have to stick with this, you gave me your word. You're right, it is your time to win the battle. The only advice I can offer is if it is feasible maybe get up from your desk and walk around a bit. Maybe walk outside for a lap or two around the parking lot, that should get your mind to not focus on the withdrawal so much. Make sure you take in plenty of fluids, help you to flush a bit and if nothing else will cause you to have to get up and change your scenery once an hour. Whatever you have to do to stay quit. Worst thing for me was sitting at my desk dwelling on it. If you need anything PM me.
-Matt