Could i have had a miscarriage

Hi, I'm new to this forum, but really wanting some advise, a couple of weeks ago I found out I was pregnant, I had some Brown discharge ( sorry tmi) and on Saturday had a tiny bit of red spotting and some pains. I went to a&e wasn't able to have scan but they did an internal and said my cervix was closed tight and the blood was old, they booked me a scan which I had today but there was no sign of a pregnancy?? I had bloods done and my hcg was 30,816 which they said was extremely high. There no sign of ectopic? I have to have more bloods tomorrow or thursday

I have twin girls 17month ago and at 7 weeks I had a scan and 1 baby didn't show then and was told it was a singleton.

Do you think this baby could just be hiding or could I of had a miscarriage even tho no pain or bleeding 

I really appreciate any advise