Hi Elizabeth,
Hehe, I used to drink Coke by the pint and knew how many pints I could get out of a 2L bottle to the nearest drop!
However, then I lost a front tooth, went and saw a dentist and stopped pretty quickly. Note, its not so much the sugar or lack of it (in diet coke), its the acidity of the drink that gets your teeth. Watch out! OK, lecture over!
Just adding my 2p, it may sound silly but have you been sneezing a llot more recently or had sore ears/sinus etc. Last year my hayfever stepped up about 3 or 4 gears and I had a lot of headaches. Only by using more powerful hayfever tablets and a nasal spray did it stop. Just a thought as my hayfever is ready to start any day, I can feel it!
Oh, and on the coke again

my dentist also told me you shouldn't clean your teeth for at least an hour after drinking your last glass of coke as your going to be rubbing the acid into your teeth rather than washing it off.
Hope you find the source of your headaches...
Ed
