Mango allergies are rare, but reported symptoms are usually generalized itching, difficulty breathing, and abdominal discomfort. Nausea is not usually associated with allergic reactions. It is possible that you have an allergy to mango, but it is more likely that your symptoms are due to another cause. To be able to make a better judgment on your case, I would need more information. Could any other factors have explained the reactions? Was this the first time you ate a mango? Were there visible signs of reactions on the skin or was it just sensations? If you want to be sure, you can always take an allergy test.