Did i have a miscarriage?

Last night i rushed home in so much pain. it felt similar to period cramps but worst. i don’t get my period because of my Birth Control so i felt something was off but i was in more need of getting home. when i went home, i did in fact start my period so i threw on a pad and passed out on my bed from the immense pain. in the morning i went to change the pad only to see a large amount of tissue in the center surrounded by blood. it’s been hours and my period has stopped but there’s still cramping going on. what was this?