When it rains, it pours! I am sorry you are dealing with all of this stuff, all at once.
I do not have any experience with the eye issue, so I can't speak to that but I think it's advisable to hold off on changing the food and the whole salmon oil thing. There are just too many variables that could be causing gas or all the stink in the house - and frankly, you don't need to deal with that right now.
So, I guess I recommend a triage method - the eye needs to be dealt with now. The rest can wait.