Progesterone dropped but normal ultrasound?


I'm slightly worried. In my previous pregnancy I was on Progesterone and ended with a healthy baby girl. I am currently 6 weeks 2 days and had my first transvaginal ultrasound. At first all we could see was the sac but she kept trying and we finally found the baby and the yolk sac. Heart rate of 104bpm which she said was normal for being so esrly. I just got my second set of labs back. My HCG went from 4872 to 47590 which is a big jump but my Progesterone went from 7.8 to 6.2. The dr office is closed so I cant call for advice. I've tried and nothing. I'm just worried at what this means even though the ultrasound seemed normal for now. Is it possible to carry full term with low progesterone?