What is this?

So my period was 11 days late (it’s normally like clockwork and comes exactly when it’s due with a 30 day cycle) and today I’ve had some light bleeding which is not the usual colour and is nowhere near as heavy as normal as this is all the blood I have had all day (which for me this is not much at all). I looked at the pad and a lot of the ‘blood’ on it is this weird stringy stuff?! What could it be? And why could my period (if this even is a real period ) have been so late??