What is this?

Hey all! I got the nexplanon inserted about 3 weeks ago. I had some spotting yesterday and mild spotting the day before, but this morning when I woke up, I started my actual period. Ive been a little crampy all day. It’s night time now and I just went to the bathroom and pulled down my underwear to find THIS. Can anyone please tell me what this is and if it’s normal! Thank you so much. Anything helps.