as for the fish, i would also add a small amount of coconut oil aka small tablespoon with breakfast as another source of fat, flax oil can also work well.
perhaps you may need to enhance your liver with some of the detoxifiers to aid in t4-t3 conversion
not to mention, your intestine and stomach health, consume some fibers and probiotics, since the rest of t4 conversion occurs in the gut, so when candida or parasites/harmful bacteria or even low good bacteria is there then the operation is mildly altered
i cant post links
but look into t4-t3 conversion and how to improve it (liver,gut)