So it's probably either stress or a reaction to fish oil.
How often do you eat fish? Is it possible you're allergic? Could you try cutting it out for a while?
I never had a problem with fish or crabs - but they probably put other ingredients in the oil of the pills who knows. I don't feel the stress at times but I feel my mind is racing with things I got to do everyday. When I told my mom what I do each day, she said no wonder your tired. You think it has gone away completely but then it returns in a lesser form of itching. So you stress about that, thinking you have some disease.