How do you quit sugar?

After a summer of living in Canada, I stopped consuming any sources of sugar except for the rare teaspoon of raw honey. I've recently moved back to College and I find myself addicted to sugar all over again, in the forms of lots of Cherry Coke and Mcdonalds, I cook by myself, somewhat a macrobiotic diet and I make sure all my meals are really healthy, nothing refined, no additives, mostly vegetables, healthy proteins, and simple grains, and I drink lots of water all day long. But at teh end of the day, I still find myself craving foods with high amounts of refined sugar, such as the ones I mentioned above. in fact, I walk a kilometre and back just to buy them. Its been two weeks and I've already gained a lb and a half. How do I handle my cravings, and deal with the withdrawal, which btw is horrible in the mornings.