Hi ladies! Expecting TWINS! Unknown Duedate.

I had a miscarriage at 6 weeks on Sep. 5th. Got a positive test and HCG blood test on Oct. 6th. Never got a period. Doctor wanted to make sure it wasn’t leftover HCG from previous pregnancy but it was confirmed that my numbers were at a zero 3 weeks prior to getting a positive. Now, I had a dating ultrasound today and I’m wondering why don’t I see that separation like I’m seeing on other twin ultrasounds. I don’t go to get results for another 2 days. All I know is there are 2 yolk sacs, and 2 babies. They’re just there dangling. I guesstimated about 7 weeks or so. I’m excited!!! But of course nervous about everything.