Drop In body Temperature

I have Diabeties and under active thyroid. I also have Fibromyalgia. I've had problems with my body temp dropping 1 degree relatively fast. Typically in the evening after my evening mea. I've checked the blood sugar and its not more than 199. What is causing this extreme change in temperature?

[Garth L Nicolson, PhD]

Response from Prof. Nicolson:  In CFS and FMS patients with underactive (also overactive) thyroid we have found chronic infections causing thyroiditis or infection and inflammation of the thyroid gland.  Candidate infections include: Mycoplasma species, Chlamydia pneumoniae, Borrelia burgdorferi, and viruses including HHV6 and CMV.  The most common infection found in these patients is a Mycoplasma infection.  Such infections can also affect the temperature controlling system in the brain.