What is happening?!?!??

Okay so first I just ended my period 9 days ago and I’m supposed to start my new period April 7th. Why why why am I spotting like this!! I have had the mirena for 4 years now and am set to get it removed on the 5 year mark because the mirena is a 5 year IUD. I’ve had things like this happen to me and I would go out and spend hundreds of dollars on pregnancy test that always come back negative. But I’ve never had it spot like this in the middle especially when my period was just last week???? I have had a few headaches but that’s normal for me.

What could this be????