Empty sac at 8 week scan

Hello everyone. 
I just went to my first check up today and got my early u/s to verify pregnancy and get an exact due date. Only to find an empty sac. The dr said my sac was measuring right to date but there was nothing inside. She had me get my blood drawn and is having me come back in two days to give blood again to see if my levels have gone up to confirm miscarriage or pregnancy. She said I could be earlier than expected and the u/s didn't detect my pregnancy yet. I don't mean to be a pessimist but I know in my heart I have miacarried. This would have been my 4th pregnancy. My others 3 were healthy pregnancies so I'm not sure what happened. I feel so alone my husband and I haven't spoken or even looked at each other since the Drs appointment. I can't help but think this is my fault. Anyone have any words of encouragement. Thank in advance!