Anyone had anything like this?

I went for my first ultrasound on Friday last week. They were not able to find a heartbeat. This was with an abdominal sonar. I had my hcg levels checked and they were over 90,000. They scheduled me for another sonor for this morning. Still, no heartbeat. So they tried the l ultrasound. Nothing. They checked my Hcg levels and they had dropped a little, but they were still over 90,000. My doctor says that my odds of continuing the pregnancy is slim and that I would likely miscarry if I had not already. I have not had any cramping or bleeding of any kind and other than the test that they are running on me all the time, I would never know that anything was wrong. Anyone ever had anything like this and not had the pregnancy end in miscarriage? Thank you for your help.