5w3d no Yolk Sac

Hi ladies! Hoping someone can share a similar experience that went on to have a positive outcome. I was 5w3d and started spotting. I know it can be normal, but wanted to inform my reproductive endocrinologist just in case they wanted to see me. They told me to come in to do a ultrasound and bloodwork to make sure everything is OK. They couldn't find a cause for the spotting and confirmed it wasn't eptopic, but they only saw a gestational sac and no yolk sac. He pressed on my uterus and tried hard to find it. He mentioned it may be a blighted ovum and wanted me to do a follow up ultrasound in one week and bloodwork. My progesterone remained the same at 36 and my Hcg doubled as it should from my previous visit. I had a misscarrige a few months ago and that was slow to grow as well, so just worried this one is not going to end well. I also know the exact date of ovulation so being a few days behind can't be the reason. Any insight and positive stories would be helpful ❤️