GCG and Chinese Bitters

Has anyone had the experience of having symptoms from taking the GCG and Chinese
Bitters herbs in preparation for a cleanse? Symptoms I'm having are extreme fatigue
and weakness (to the point of having to lie down in middle of day), strange pulsing
headache just on one side of head, top of skull, trouble concentrating and remembering.
Also, stiff neck at base of skull when awakening from night's sleep.
Just curious if the herbs could have anythihng at all to do with it. I find it coincidental
that they have been happening for just around the same length of time I've been using
the herbs. Thanks!