Miscarriage

Last night I had the worst experience of my life.. I had all this blood coming out of me.. I was sure I was losing my baby. But the ER did an ultrasound everything was normal. The baby is growing, heart beating and moving around. My cervix was also closed... So basically they say there's nothing wrong with the baby.. Has anyone ever had something like this happen to them? Do you know why you were bleeding? Did you make it?