Has anyone been through this?

AF is 6 days late, tomorrow will be a week. The question here is, I've had very very light bloody mucus,  (tmi) sorry girls, but no sign of starting, it's so faint that if I wasn't looking for it I wouldn't even notice it, and it's not an all day thing just once or twice throughout the day! Tested 5 days ago and got a bfn. Has anyone had any of this happen before... We are 3 months in with TTC with baby #2!!