My NutraSweet experiences are similar. A few years back, I started experiencing severe Arthritis-style joint pain. Went to every doctor in the state, with no results. They could find nothing.
Suspecting NutraSweet, I swore off the stuff. The results were amazing, but it took a year for thing to get back to normal. Which includes my normal water skiing, skydiving, and weight lifting.
A few days ago, I accidentally swigged down a whole “Arizona Iced Tea” with Aspartame in it. All the pain came back big-time!
Hope it goes away quicker than last time.