Hi Emma,
Congratulations on your decision to "quit". If just stopping is just too difficult, perhaps it would be an idea to see your doctor and have a glucose-tolerance test or check if you have some condition which is stopping your brain ruling your body.
David's book SWQP has lots of advice on pages 80ff on how best to handle withdrawal.
One of the best is to keep a "sugar diary" for say two weeks. Weigh and measure everything you eat and estimate the fructose content from the "sugars" % on the food Nutritional Information Panels, plus the tables and graphs in David's book. If it exceeds 10 grams per day, you need to cut out all the high-fructose foods.
Two to be especially aware of are low-fat" foods as the flavour that gets removed with the fat is often replaced with sugar and salt. The other is fruit juice - it's concentrated fructose and just like drinking fat. Dried fruit is similarly concentrated fructose. Most breakfast cereals should be in the confectionery aisle of the supermarket, they are so heavily loaded with sugar.
If none of this works, perhaps you have emotional issues around "comfort food". In other words, you may be using sweet food to control undesirable emotional reactions to the world. If this is the case then you should consider engaging in a course of counselling with a therapist.
Sharing experiences with other like-minded people is always helpful too . . . "you are not alone" :-)
Do keep us posted on your progress. Believe me, it really is worth the effort.
JohnN