Hi, Im Nala. I just started back on my PKU diet as of May 26, 2010. It is not very easy after being off of it for over five years. I seem to be having a hard time adapting or at least my system so far. Today one of my symptoms was a headache. The headache felt as if my head was about to explode. I had a hard time with the light or the brightness of it. I could not even touch my hair it hurt much less lay down without hurting my head. I would like to know did anybody else have these reactions. My formula is Phelexy-10 tablets. Did anyone else have headaches? I am going back on the diet because i want to be there for my children and because of the new research they have done which made me question my health.