Has drinking Crystal Light made you feel poorly?!

Has drinking Crystal Light made you feel poorly?

I have drank Diet Pop for the last 10 years and have been in peak physical condition. I still drink it, but recently have replaced a few pops with Crystal Light. I am having terrible headaches, and my neck feels swollen? Doc says it's migraines, but I am skeptical. My only diet change was the intro of Crystal Light. Has anyone had any bad experiences with it?

2 weeks ago
I am still drinking alot of pop, so it is not caffeine withdrawal, and C-Light has less aspartame/nutrasweet than does pop.

i used to drink diet pop pretty often, and now i drink like crystal light every day, and i have no problems at all.