Save the will-power for things like not eating an additional slice of pizza. We are talking about an addictive opiate not that different from heroin. It takes down people all the time with histories of self-discipline. Like herbavore wrote, find support and furthermore a variety of options for help.
1) Suboxone detox. Find a doctor and set up a rapid taper and see how that goes. Or obtain it a different way, but a doctor means not breaking the law.
2) AA/NA. Not for everyone, but at least find out it is not for you by giving it your best effort. You just might love it!
3) Friends/family. Tell people you can't do it alone and need help. Sure, a lot of people look down on drugs, but most respect (if not totally want to support) a person who wants to get off drugs.
4) Change people, places and things. Write out three lists of all of the people, places and things in your life right now. Then for each thing on each list ask yourself "does this help or hurt my effort to quit?" Cross off anything that hurts you. What is left, well there is the basis for your new life. Start adding new things to it that your mind does not associate with drugs or the scene.
5) Start working out and eating well as soon as detox ends. These are healthy replacement addictions for your addictive personality to latch onto. Getting in shape also does wonders for natural endorphins and self-confidence. No more need to have synthetic versions when you got the real deal.
6) Support meds. The first few weeks off are rough. Immodium can help an upset stomach (and other symptoms). L-tryptophan, camomile tea, passionflower, hops, melatonin, along with vitamins. Stay hydrated. Your doctor might give you stuff for sleep, blood pressure, etc.
The goal is to find stuff in recovery that you enjoy more than getting high, so that will-power is removed from the equation.
It is really hard at first. Most of us have been there. By 30 days you should feel like a totally new person if you get through it without using. You got it.