Fetal heartbeat found at 6wk6d then nothing at 8wk2d, can I still be pregnant?

I had my 1st OB/Gyn visit on 4/14/09 and the Dr found a blood clot and also a gestational sac, yolk sac, fetal pole and a heartbeat. She calculate that I was 6wk6d pregnant. On 4/24/09, My husband and I went for my 2nd sonogram. I was 8wk2d. I was told that there was no baby on a gestational sac. I was told that I would miscarry and should have a D & C. I choice to miscarry naturally. Today, 4/29/09 I spotted a little so I went to hospital. They did another u/s and I was told that there was a baby only no heartbeat. I am completely perplexed. I don't know what to believe. Is there any hope that maybe a heartbeat just couldn't be seen? I am soooo emotional. Has anyone had this happen to them and they didn't miscarry?