Early Ultrasound.. measuring behind.. nervous

I went in for an ultrasound today due to cramping & there was only a gestational & yolk sac & what she said looked like possibly the start of a fetal pole.. based on my LMP I should be 7w6d today but she said I’m measuring about 5w6d. My cycles have been irregular & I do think I ovulated late so she said all looked fine & we’ll just have to do a repeat ultrasound in 1-2 weeks. Anyone else had a similar situation & all turn out ok? 🙏🏼❤️