I would try activated charcoal powder. You can get it at a health food store. You can get tablets or powder.
Take 4 tablets 3 times a day, or 1 teaspoon three times a day, always with a tall glass of water. Here is some information about using charcoal to detox from aspartame:
You can also take an epsom salt bath to help with detoxing your body. 1 cup epsom salt in a tub of very warm (but not uncomfortable) water for 20 minutes or so.
I hope you feel better soon.
~Mama to Many~
Detoxing From Chewing Gum
Dany, NAC is the supplement that helps with this type of overdose: http://www.futurescience.com/nac.html. I hope you fell better soon.