Five week ultrasound gestational sac but, no yolk sac

Amanda • Mommy to our angel baby, Jack💙11.11.18 👼🏼 he was born at 30weeks, passed away 12 hours later in my arms. We are expecting our rainbow baby due on 10.20.19 💕💙 🌈

I am 5 weeks 1 day pregnant & I had my first ultrasound today. I had my ultrasound early because I am high risk. In Nov. 2018 I gave birth to our son at 30 weeks & he passed away 12 hours later due to birth complications. Today’s ultrasound only showed a gestational sac. There was no yolk sac or fetal pole. My doctor said the dates can be a bit off leaving me a few days behind... or the baby may not develop and I will miscarry. I feel really nervous and upset. Has this happened to anyone & have you had a positive outcome? We go back in 8 days for another follow up ultrasound. I will be 6 weeks 2 days then. My Hcg and progesterone levels seem normal but, they were retested today. I will have those numbers back tomorrow.