Miscarriage

I was supposed to be 8 weeks pregnant and going to my first official appointment when I started bleeding right before going into the office. They sent me to the ER as I had been cramping badly the whole day. When I arrived at the hospital there was no sign of baby in the ultra sound, I went back two days later for some more blood work and my quant levels were very low which is a sign of a miscarriage. I have been bleeding for three days now and I don't know what is supposed to happen now? How do I know if I have miscarried yet? How long does it take? How will I know if I am clean now? So many questions