Drugs have fluorine too
Here is a link where I ran into this subject before. One of the links inside has a site where you can put the name of the drug in and see if it has fluoride in it.
//www.curezone.org/forums/fm.asp?i=920165#i
As far as the headache, when you think headache, think salt push. Repeat the salt load with 1/2 tsp salt as many times as necessary.
Also, since you drink tea, try to notice if headaches are connected to caffeine in any way. I get them with caffeine withdrawal, but since Mountain Dew has so much caffeine, and so many chemicals, I would suspect it would be caffeine overload. Vitamin C will counteract caffeine overload.
By the way, green tea has twice the fluoride as black tea. However, my theory is that under normal circumstances, natural fluorine will not cause as much harm as added fluoride. Just my theory. Since your health is compromised, you may want to research it and see if you agree with me on that or not.