I too used to consume sodas with NutraSweet. I used to get headaches, severe mood swings, etc. I finally figured out where it was coming from: NutraSweet. Then I researched and information made me believe even more so this was the case.
My wife received a liver transplant 4 years ago and the hospital suggested that she stay away from dark colas, and one person suggested staying away from NutraSweet. Neither of us touches anything with this substance. It is definitely bad stuff. We bought Vita Mix mixer/juicer and what we made blows anything a soda could ever taste like. And it is way cheaper too when you handle fruits right.
NutraSweet. Bad stuff. Very bad.