I recently went to a Mexican restaurant with my fiance. I have a documented shellfish allergy, and therefore told the waitress I can't have anything with fish in it. I ordered a chicken fajita, and within a few bites, I started to feel very odd. I was dizzy, my stomach was on fire, and I felt excrutiating stomach pain. Usually I get hives, so I didn't think this was an allergic reaction. I didn't finish my dinner, and we had to go right home. I was sick all night, eliminating everything in my system. It was some of the worst pain I've ever been in. Still, I thought it was food poisoning. Usually I get hives, and then the abdominal pain. I took the food out today just to look at it, and there were two tiny pieces of baby shrimp mixed in with the chicken. I did not, however, go to the ER.
Unfortunately it appears that the restaurant was careless and because of that you had a horrible experience. However, if you did not require medical treatment you do not have special damages. (Special damages are documentable expenses such as medical expenses and loss of earnings.) In the absence of special damages, a jury is unlikely to award much, if any general damages (e.g., pain and suffering). Because of this, it is probably not worthwhile to file a lawsuit. However, I certainly would speak to the managment of the restaurant. They will likely offer some sort of concession, such as a gift certificate or discount coupon.
This response is for information purpose only and does not constitute a legal advice. This response does not create an attorney-client relationship.