Late period with mucus

So my period is 12 days late, I took three home pregnancy tests about a week ago when it was only a couple of days late and went to the doctor and they did another, they all came out negative. I have PCOS so it's really difficult to get pregnant, not to mention the irregular periods sometimes. But today o sat down to go to the bathroom as soon as I woke up and there was a thick clear mucus with some pink strands in it.. No period though. What could this mean?