HELP!😭 I think I had a miscarriage!

I've been on birth control for about three months and I just started my period today and this thing fell out of my vagina! It's empty but I'm light freaking out cuz I'm 17 and my parents don't know I'm sexually active. If this is a miscarriage, I will NEVER have sex till I'm married...UDATE: it's been a while but I've went to the doctor and he said it was just uterine lining!🙌🏻