All artificial sweetener upset my stomach and/or gives me headaches. Even when I eat something and I have no clue what kind of sweetener has been used, if I get sick from it I start reading the nutritional label. Without fail, it will have an artificial sweetner in it. Sometimes, I can't even recognize the name of it, but I look it up online and sure enough, it's just another fake sweetner.
So, everybody is different. If something makes you sick, and when you stop eating it you aren't sick, you'll know what not to eat. Just listen to your body.s