Jen, personally I feel safer using Splenda than Equal or sweet-n-low. Splends just feels more natural, doesn't give me a headache, etc. If you are really worried, try using Stevia. Though it is not accepted as a sweetener here, it has been used for hundreds of years across the world, and is made from an herb. My doctor has heard nothing against it, though there have been no official trials in the US, which is suspicious. You can get it at a health food store.
Your call...I drink organic milk too. We have to feel safe about the food we eat. Do what you need to do, okay?