Hi, I had what was officially diagnosed as a blighted ovum in November of last year. My story is a long one, but I want to share it with you because I think it will still give you hope.
I had a pretty rough start to my pregnancy. I was extremely nauseated and feeling run down for a few days. Right at 6 weeks, I started having cramping combined with brown spotting (only twice). I went to the ER that night. I found out at the time my HCG level was 6,000 and the scan didn't show anything but an empty sac. No yolk or anything. I followed up with my OB two days later and my HCG had doubled to 12,500, but they found out my progesterone was low at 7.1 (it is supposed to be over 20). They had two theories - either my hormones were low causing delayed fetal growth or I had a blighted ovum. They were reluctant to believe it was a BO because my HCG levels were rising appropriately and were getting quite high. I was so distraught. I thought for sure they had written my pregnancy off because they wouldn't even treat my progesterone.
Two days later, I went back and my HCG was now over 25,000. I demanded another scan. At the bedside, they immediately found a fetal pole, but couldn't see any heartbeat. By this time I was 7 weeks but still hopeful. They decided to start treating my progesterone and hope the baby caught up. One doctor still tried to tell me it was a BO. I just didn't believe them. Four days later, I saw a HB! It was low - around 96, but measuring right on for dates. Still, they were not hopeful due to a low heart rate. My HCG was well over 50,000 by this time. They renewed my progesterone Rx for me and became more reassuring that things would work out. To make a long ending very short - the pharmacy made an error with my progesterone and only gave me a fraction of what was prescribed to me. I miscarried a week later, but it wasn't found until my 11 week visit. I can't help but think if the progesterone dose had been correct that my situation would have been alot different and the baby would have made it to term. The doctor seemed to think the same. In the end, one doc said it was a BO, another said it wasn't. There is no clear set guidelines of what makes a pregnancy a blighted ovum because all of them are so different.
Even though my story didn't end like I would have wanted, it goes to show you that the doctors are not always right!! Your HCG levels CAN be over 6000 and not see a yolk. My levels were over 25000 before we saw a HB! Don't take loss as an answer from them until everything else proves otherwise. I have alot of hope for you! You might even want to go on misdiagnosedmiscarriage.com I found alot of support and hope from some of their stories when I was going through this and they helped me understand things a little better.
I understand what you are going through, believe me. Just don't give up hope!
You are still so early on, there is no way they can tell you with any certainty your pregnancy isn't viable. Message me if you ever want to talk. Best wishes!
and ill keep my fingers crossed everything works out ok 
And I just had my 12 week U/S yesterday, and everything is fantastic. Baby is even measuring 2 days big!
