There is one thing that you can try for curbing your cravings...dill pickles. It may sound funny, but it works. It'll help you control the cravings while you are weaning yourself off of the sugar.
You recognize that you are addicted to sugar and it sounds like you would like to get off the craving treadmill of sugar, snacks and candies. You are asking if there is a substitute for sugar. Unfortunately there is not.
You probably know that there are many sugar substitutes available, such as aspartame, saccharin, and the natural sweeteners like Stievia. If you are not a food addict, these might work - I would suggest that you try and see if eating sugar free snacks that have these ingredients satisfy you. If you are a food addict, then these will NOT work. Food addiction is a chemical dependency on the 'sweet' taste itself, so even honey, fruit and good sugars can be problematic for a food addict.
An interesting study on rats showed that they preferred saccharin over cocaine - just the sweet taste alone made the cravings worse. If you switch a substitute for sugar, chances are that you will still crave sugar. It is like an itch - you can scratch the itch with your fingernails or with a wooden back scratcher or with a wet cloth, but the very scratching makes the itch worse.
Often people who are sugar addicts will try to eat starches instead. They will go for the 'savoury' rather than the 'sweet'. Savoury items are still quite starchy, and so are 'hidden' sugar. The very nature of addiction is that nothing can satisfy the cravings for long .... if it could, there is no addiction.
The only way for the cravings to go away is not to FEED them, but to STARVE the cravings. If you could stay away from sugar or refined starches such as bread, bagels, chips (which becomes sugar in a matter of minutes) for one month..... the cravings would lesson and eventually disappear.
I know that this is not what you wanted to hear! I know that if you stop, you will likely have to face a good few weeks of withdrawal and increased cravings. It isn't easy. This is the power of sugar addiction. I have many patients who say that they can quit cocaine, alcohol, even smoking, but not their candy or chocolate. You are not alone.
Good luck on your week - see if you can make it a week longer to two or three weeks, and you will find that it will start to get a lot easier.