Ever since I was young, any time I would eat shellfish I would get really bad headaches, would vomit for hours, and I would get a fever. It was to the point where I had to drink water to vomit up so that I would feel some relief. I discover this when I was around 10 years old, and it did happen on many occasions with the same symptoms. My family chalked it up to allergies and I tried not to eat shellfish again.

I few days ago, I was eating some dumplings with my roommate and fond out afterwards that there was shellfish in the dumplings. That night I had severe headaches, fever, and nausea. There was no vomiting so I don't feel any relief, and it is lasting much longer; 4 days total.

First question: are these allergic reactions?

Second: can the second occurrence be any allergic reaction?

Third: Is there anything that I can do to relief this pain?

Thank you,

Michael