Curious about others experiences with low progesterone

So my progesterone is at a 5.3 at 5 weeks pregnant and we had an ultrasound and it showed there is a size appropriate sack and my hcg is doubling every 1.4 days and is currently sitting around 3,500.

Obviously my doc started me on progesterone and I start tonight. (Unfortunately several days after receiving the request to, but better late than never I suppose)

But after looking and the most recent medical articles and research. One initial progesterone reading by 5 weeks with a result of >5. is enough to estimate a 91% chance of miscarriage.

I am so freaked out half of my medical team is really concerned and the other half doesn't seem concerned at all.

Does anyone have any success stories of progesterone with a starting level as low as mine?