I think you made it more difficult for yourself than it could have been. Have you read any of the fasting and natural hygiene books? There are many available for free online. If not then having more knowledge would have helped you to minimize your misgivings about the safety of fasting. Now that you have experienced a 15 day fast you will be better prepared if you choose to fast again. I think it's likely you did have some long term benefits you are not aware of. Your body had 15 days to remove toxins that were building up for many years. This will certainly benefit you in the long run. Good job going 15 days.