Feeling so defeated

I did IUI and conceived on my first try. So there is no way my dates are off. Had my first scan at 6 weeks and could only see the yolk sac. Went back yesterday for another scan at 8 weeks, there is a fetal pole but it is measuring at only 6 weeks but no heartbeat. Dr only mention it’s a slow growth and there’s progress from the first scan but other than that didn’t seem too concern and scheduled for another ultrasound in 2 weeks. Give it to me ladies, any advice or experience?