Gross photo warning!!

So I’m 2 months postpartum, have Nexplanon birth control and finally got a period. Last Friday i changed my tampon and this huge piece of flesh came out. Not sure if that’s normal from having a baby or my body is just cleaning out. What do you think? I tried to tell my doctor but they couldn’t get me in. I doubt it was a miscarriage because i just had a pregnancy test before i got Nexplanon on December 13.