In my opinion, the reason you got nauseous is because you broke one of the cardinal rules of liver flushing. You are not supposed to eat any fat the day of the flush. The fish you ate, although good fat, are full of fat. You need to eat fat-free all day to allow the bile to build up so that once the virgin olive oil/grapefruit juice mixture are taken the gallbladder ejects the gallstones. I have read that eating any type of fat the day of the flush can make you very nauseous. I hope this helps.