12 weeks and bleeding

Kelsey
Yesterday I went to the bathroom and bright red blood when I wiped... it completely caught me off guard. I had no symptoms of its onset, I ended up going to the ER and they did an ultrasound and the baby is fine. Moving around and a heart beat of 167. They didn't see any active blood around the uterus and my cervix was closed. They aren't sure why I am bleeding, I have no cramps. Has anyone experienced this?