I am starting to introduce a bottle to my LO, 4months old, so she can start going to daycare. I have been pumping and thawed some milk today that has been frozen since Feb 2 in a regular freezer. It smells fine but when I tasted it, it tasted off. Not rancid, just off and a little fishy. Is it ok to use? And is this normal to have a change in taste like this from freezing?