Weird vaginal stuff

So, I am 14, not sexually active, and I started bc a month ago. Today, day 49 of my cycle (late period) I started my period. I am having extreme menstrual cramps, kind of like what contractions are supposed to be like, and when i went to the bathroom, there was a peice of something that looked like skin in my pad. It was about 1 1/2 inchs long, relatively thick, and seriously looked like a piece of skin. What the FUCK is it? Anybody know? It isnt like regular fluid, it was more solid.