Blighted ovum

Hi. I went in for my first ultrasound for this new pregnancy around 5 weeks 4 days and there was just a gestational sac and no yolk sac or fetal pole. I went back at 7 weeks 4 days or so and same story but the gestational sac had grown and now I’m going back a week and 2 days later to see if there is something more but I’ve been told it looks like a blighted ovum. The doc seemed pretty sure. I have PCOS and this would be my 2nd child. I also have a tilted uterus. Does any of that affect the chance that it’s blighted ovum or may not be? I took a blood test after the first ultrasound and one last week at the appointment where I measured 7 weeks or so. I plan to compare the HCG once I get the results from the 2nd one. It might sound silly but my belly felt bigger prior to getting the news that it might be blighted ovum. Now it feels more normal. Can progesterone help? Thoughts?