Two yolk sacs no poles one gestational sac

Joe

My wife and I went in for our first appointment. She is 9 weeks after her missed period but after looking at our ultrasound the doctor said that it could be 6weeks and a day.

So we are able to see two yolk sacs. One is easily visible and the other looks a lot thinner membrane and was not visible the whole time.

Would could this mean? Does this mean it’s twins? Is it still possible that it could only be 1 baby? Thanks. I’m just thinking about it all the time and she is also stressed about it. What are the possibilities? I have no idea what to think and we have to wait another 3 weeks to go again.