Messed up cycle

So I had my Mirena removed late January and got a normal period in March. Since then, the cycles have been fairly normal. I got AF a week early for my July period.

I have been trying opk’s. I had a positive opk on 7/13. I thought this was probably too early to ovulate. This evening when I went to the restroom I had what appears to be old blood. What is going on with my body and cycles?

I tested earlier today because my sense of smell had been heightened and my nipples are sore/tender. It was negative.

Any insight would be greatly appreciated.