Fish
I have not had that reaction however I have noticed that the fish I have eaten post op tastes a lot fishier than it used to. Of course taste does have something to do with smell so there might be something to what you are saying. I might just have a much milder version of what is going on with you.
I have never enjoyed eating fish like salmon as they always tasted too fishy to me. I used to eat a lot of tilapia as that is a mild fish. Now the only way for me to eat it is if it is covered in something that masks the fish taste. The Mrs. Pauls Parchment baked Tilapia in either the grilled or garlic versions are too fishy but somehow the lemon peppercorn isn't too bad to me. The sauce is thick enough to mask the fish taste for the most part. Sometimes I have to go into the fridge and find something else to cover up fish. One of my favorites is a Walden Farms BBQ sauce (0 calorie) with a Yogurt based Blue Cheese dressing. Kind of giving it a black (spicy in this case) and blue (blue cheese) flavoring that covers the fishiness.
Anyway it wouldn't surprise me if you are having this issue. Sorry to hear that though as fish is good for you nutritionally. Flaxseed is a good alternative for your Omega 3s. Flaxseed also has 4g carbs which are from 4g fiber and 5g protein per 2 tablespoons.