Blood at the bottom of container

So when I pump I put it into a container and into the fridge, in rotation. Today I looked at the front container and it looked like ‘blood’ had sunk to the bottom of the container. When I shook it, it looked normal again. I picked at my nipple yesterday and it bled so I’m assuming this may be it, but is it safe to give to baby still? There’s no other way it could have been contaminated with anything else but it has freaked me out slightly.