I get a reaction to aspartame - I can’t tolerate the stuff.
Same with anything ending in “tol” -malitol, sorbitol, xylitol
Eating at a restaurant can be challenging....
If the reaction you experience was caused by the aspartame, you would get a much more violent reaction from eating a piece of chicken with a glass of red wine, or apple juice, or orange juice, or red grape juice or tomato juice.