You have to do enema every day. You have to wash your intestines, or you will continue to have headaches. The posisonous stuff returns thru the intestine walls re-entering your your blood stream. That's where your headaches are coming from. Washing your intestines removes this and you will feel refreshed and clean in your head.
It is quite simple, you needn't be afraid of it. It is an everyday thing once you get used to it.
Please, don't continue hurting yourself. If you want to be healthy and feel ok while fasting with water, just do it.