Threatening miscarriage

I started bleeding yesterday right after work. I went to the ER as my first prenatal visit isn't until March 5th. They checked my cervix which was closed. They checked my HCG levels which went up from last Thursday at 1700 to 5900. Did the ultrasound and baby was measuring 6weeks 2days but they couldn't find a heartbeat yet. They said I had a hemorrhage in my uterus which may end up leading to a miscarriage or may not. Today I am bleeding and cramping. Anyone else had any experiences like this. I am so scared.