Fasting bowel motions are the grossest I'm sure all will agree. The pain you felt after ending your fast could have been due to how you broke it unfortunately. Communion isn't much food wise so it probably wasn't that, but the digestion system is far more sensitive after several days or more without eating and needs to be eased back into it on natural high water content foods. This means raw fruits, and the longer you fast the smaller the quantity you need to eat at first. Choose high water content fruits first up, melons are excellent but most fruits that are in season will suffice. You should also try to stay on raw foods for the amount of days that you fasted for. There should not be any pain with your bowels if you do this, though there could be old blockages being moved in there that your short fast did not have a chance to remove before you ended it.
Here is a list of fasting retreats around the world. They would be a good place to start in contacting someone close by. On the same website you will find an Advice page where fasting supervisors can be contacted for consultations via the internet or by phone if you are not close to them.