So... if the previous tapering attempts were perfectly uneventful, I would say those should be mostly uneventful as well even more so that you seem to be following a strict schedule.
About weakness: sometimes supplements do not agree with people as @Catina said. When they don't, the most common response is probably weakness / fatigue. The most common response to any illness or problem out there is weakness / fatigue, though. I would say you must keep in mind there might be yet another unknown cause, and you must keep in mind you can drop the omega 3 oil entirely at any time to ensure it's not that thing causing weakness.
Is there a chance you got infected from your children? I never, almost never got the flu but when I got it, that was exactly when living with someone who had a flu. You can't make a diagnosis based on little info and little info points.
When you do not have enough info points, and cannot prove a theory, you come up with an experiment and run it. So, in this case the "experiment" would be watch your body react to dropping to one pill of omega or even drop it altogether.
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