what is this ?

i just got out of the shower i peed and wiped then I saw this what is it ? I’ve been on the Mirena IUD since September 12th. I’ve had 2 periods since I got on it , I’m supposed to start my next one tomorrow. I’ve been having pinkish / brown discharge since Saturday. I was having all the pregnancy symptoms and pms symptoms. I’m just confused on what my body is doing