3 weeks behind???

So my last period was September 25th, I received a positive opk October 2nd and then I got my positive test October 12th. I went for my ultrasound today and I was suppose to be 9 weeks and 2days, but I measured 5 weeks and 4days with a yolk sac. They did not offer hcg testing for my levels and I had to argue to get a scan December 3rd. They had nurses sent in and all they told me was I was going to miscarry. Has anyone else had this and everything turned out fine??? I’m trying to be hopeful that I have a yolk sac but the 3 weeks off is very upsetting. This will be my 3rd miscarriage if it happens and I’m just upset I’m not getting more help from the clinical staff.