I have that as well. The first time I had it I thought I had food poisening but it was just aan allergic reaction.

It's the reaction your body is still suffering from the food. The one time it took me almost a week or two to feel normal again.Good luck healthy food and lots of water

I used to get this before I figured out that my allergy had got worse.

Can I ask how you managed to eat the fish in the first place if you’re allergic?

I call it an allergic hangover. It's miserable!