A few years ago, I overdosed on aspartame. Yes, it's possible!
I used to drink a lot of coffee (like over a gallon per day) and sweetened it to the tune of 4 aspartame tablets per cup. One day all of the sudden, I became very fidgety, my blood pressure shot up and I nearly fainted. I went see my family doctor immediately, and he said it wasn't the coffee but the aspartame.
So I quit aspartame cold turkey, and for 3 or 4 weeks, I felt craving. I kid you not, I felt like crap and wanted the stuff bad. And then it went away.
I now avoid aspartame like the plague. I sweeten all my drinks with stevia now. That's real stevia, sold in fine powder that requires no more than a knife's tip per cup of coffee, not the fake stevia/aspartame/matrodextrine mix sold in compressed tablets by big sweetener corporations.
Real stevia takes some getting used to, as it has a strong licorice aftertaste. But after a while, your brain learns to ignore it. Just like it learns to ignore the buttery taste of VG if you vape it long enough.
I think aspartame is toxic. I have MS and it messes me up something awful. Plus, all the research I've done on it, I have yet to see anything positive. And it's in gum and diet sodas...YUCK!