Welcome to the group, I think you better stay clear of
aspartame as well as Splenda. I had severe problems
with both including vision problems.

I am a little confused because you said you drank
Sprite zero to avoid aspartame. I thought Sprite zero
has aspartame - I just looked it up and according to
this link:

http://www.answers.com/topic/sprite-zero

it says:

As artificial sweeteners, in its North American
formulation, one 355-ml can of Diet Sprite Zero
contains 75 mg of aspartame and 50 mg of acesulfame
potassium.

I am not sure what acesulfame is - but I am sure
someone here does.

The best thing I have found for a zero calorie pop
type beverage is to buy carbonated water and put
flavored Stevia drops in it. You can buy them in some
health food stores you can also find them on the web -
Amazon.com even cares them, my favorite is the
rootbeer flavored and the Grape.