Cane Sugar and Citric Acid

[JPisME]

Is there any known condition or biological circumstance which can make an individual sensitive to the combination of these two nutrients? I had a stomach flu a few weeks back, and since its passing I've noticed I get mild diarrea and loud, weird noises coming from my stomach/lower intestines whenver I have this specific green tea (made with natural cane sugar, and enhanced with Vitamin C), or Vitamin Energy.

I have also noticed my appendix area is a little irritated but I'm a little unsure as to how that would be relevant considering only these drinks give me problems now.

Any ideas?