Plan B

10/12 I had unprotected sex and took plan b on 10/14. After I took the plan b I had experienced cramping and spotting all day the following day. This morning 10/16, when I woke up there was a small clump of discharge (probably the size of a nickel) I have never seen anything like that before so I pressed on it and it was able to separate and stretch like uterine lining, flesh like. Does anyone know what this could be?