The caffeine could be giving you the headaches and, if you aren't getting enough water to drink, you could be dehydrated too. So much sugar can give you headaches and other upsets also. I'd work on my diet, see if I could drink less soda and eat better food (an apple a day keeps the doctor away can really work :-) I got cans of seltzer water and drank some of them pretending they were soda, you'll wreck your gut pretty fast if all you drink is soda and that's not fun.