Markus,
Body chemistry is everything as you have experienced. Too much or too little of any chemical in the body wreaks havoc with our physiology. There is one organ in the body that controls every gland in the body. The nerve system - brain and spinal cord. Now let's say that there is interference in the brains ability to effectively regulate these glands, then we we get too much or too little chemicals released. I would HIGHLY recommend seeing a trained chiropractor who will look for interference in your nervous system. This may be the cause. I am not syaing it is, but if your body's chemistry is not functioning properly, this is the first place I would look.
Haze