Has anyone seen a twin pregnancy on an ultrasound at 7wks?

Please no negative comments, i dont care to read em & theres nothing wrong with asking for advice or opinions.

They told me its a yolk sac but i didnt see an yolk sac with my other kids at 7ish weeks. On my ultrasound it says 8weeks but after measuring the baby, they said i was only about 6 weeks 6 days. Ive googled (i know i shouldnt trust google 🙄) but none of the yolk sacs i saw on other ultrasounds around the same time looked like this. they were pretty much perfectly circle. Am i just over thinking? because everyone around me has been telling me since i took the test that it was twins & then this is the ultrasound i recieved. So maybe im just being paranoid lmao