What is this?

A few weeks ago I had pink milky discharge. His was a whole week before my period and I got really freaked out. Never happened before! This was before I had Glow so I don't know if I was ovulating or not. My s.o. and I have sex at the very least one time a week. I don't understand what this is. Could it be implantation? I've heard many stories of women who still have their period and are pregnant. Should I take a test?