You will need a few days to transition back to food from a 7 day fast so you won't have time with the wedding in 8 days (you don't want to be sick to your stomach on your big day). A few day fast won't change your weight much because as soon as you eat it will return (first few pounds are from no food in your digestive system). Also the first days are often the hardest. Mixing that will pre-wedding stress could be a disaster.
If you are looking to trim the tummy area you can buy a neoprene belt/wrap around from a sports store (near the weights). You wear it while working out (or doing chores or whatever) and it sweats out the water in that area.