What is this?

Suprena

So I am now 2 days late. All tests have been BFN. I had a complete natural MC on 7/7 and first cycle 8/2 (Normal). I just went to the bathroom and had light pink watery blood in my liner. I've never experienced this. If anything I've had dark brown blood to start a new cycle or bright red. Any insight as to why it's so watery and light?