Hi Sooike,
I've experienced that type of reaction with drugs (sulfa) that I'm allergic to, but never with food. I guess I have an intolerance to avocados myself...my stomach burns really, really bad, get nauseated, shakey, and sweaty. I had the same reaction to shellfish for a couple of years before it turned into full blown anaphalaxis (suffocation, basically) from eating it. I haven't been able to eat shellfish for about 14 years. Your experience may very well be an allergy. Everyone's body reacts differently.