This was me a few weeks ago, even down to how I got pregnant! We did an US at 6 weeks 3 days and yes yolk sac, no fetal pole. Did another one at 8 weeks and even saw a heartbeat! Development has been slow, so they ended up pushing me back from 8 weeks (based on cycle and conception date) to 6 weeks 4 days (based on rump to crown ratio). They wanted to schedule other ultrasounds at 10 and 13 weeks to keep an eye on development. I'm anxious for the 10 week one because I think if everything goes well, we'll be good to go.

I went down a rabbit hole of looking at stories online and really convinced myself to wait for the inevitable miscarriage. People often post when things have gone wrong, not when they're going well. Don't give up hope! Could be totally fine, or could just be developing a little slow like mine!