I have finally discovered why I was down feeling like my head was going to explode. I was too "pou" - meaning.. having a bit too much good quality herbs to nourish my body. Strange though. I am suppose to nourish my body and it gets ill because it cannot take the 'nutrients' from the Yomeishu.
I have stopped taking it since. Will probably resume in a week... at the moment, I am drinking like a horse ... even the water in Spotty's bowl is beginning to look interesting (Spotty is my sis' dog).