nurse practitioner said possible twins

I had my viability scan today, I'm measuring 6 weeks 1 day, by period I am 6 weeks 3 days! She saw one healthy baby with a heartbeat and then saw something else that she said she couldn't quite tell what it was.

She said it was either another baby who stopped growing and had no heartbeat or could be another viable baby and its just to early to see

Has anyone else had this experience? Did you end up having twins or a single baby? Either way I am grateful for at least one healthy babe! Just super curious/anxious!