first pregnancy worries

Amber
A day before my first appointment i was spotting brown intermittent which eventually went away. The next night I passed a fairly large clot and was bleeding a decent amount into the night which filled a pad. I had mild cramping, the normal pregnancy ones nothing where I was doubled over in pain. I did have slight low back pain. I didn't have a fever and my spotting/bleeding completly stopped. I just got my blood results back and my doctor said that my levels were a little low. My ultra sound results showed an empty sac and that I was actually around five weeks pregnant. My doctor wants me to wait it out and get more blood work next week. She said it looks like a miscarriage. Also my breasts feel more tender than they did two days ago, so I'm just really confused. Does this seem normal to anyone. Or has this happened and the baby turned out fine? I'm just having a hard time waiting for a definite answer.