Pammi,
Sorry to hear about your reaction.  Did you seek medical help?  Remember, we
are just a support list!
I would suspect the calcium disodium substance.  Minute Maid OJ drives me
crazy, and it has a calcium additive.  I am fine with other natural/ organic
oj's with no additive.  The Minute Maid may be calcium lactate,  I can't
remember.  I would be suspicious of any ingredient which is vague
"artificial flavors" or any words you can't understand.  When I was on a
strict milk-free diet, I did best with organic and natural foods whose
ingredients I could understand.
Cross contamination is also a very likely suggestion.
good luck
Christy