What is happening?

I'm suppose to be 8 weeks. Ultrasound yesterday showed I am measuring 6 weeks and there was no heartbeat. My hcg was 14,615 last night and will have another test tomorrow. She said those are reassuring numbers. My last period was Sept. 18 and I ovulated Oct. 2nd. Anyone with similar experience? Or just some prayers. This is my first pregnancy and I am devastated that something is going wrong.