Serious help.

I just got back from the doctors after being there for 6 hours.. i just had an ultrasound 3 days ago and I'm 7 wks, 2 days and the heart beat was 154. I went to the er because I was bleeding. They couldn't find the heart beat but I just heard it a few days ago. They told me it was a possible threatened miscarriage.. has anyone else gone through this? First baby and I'm depressed already.