HCG rising slowly at 8 weeks

So I had my hcg tested at 6 weeks and it was around 40,000. It had been doubling normally (in 24-48 hours) until then. They saw an embryo and heartbeat at 7 week ultrasound.

My doctor ordered a progesterone test for me recently and they tested my hcg again as well at the lab. This was at 8 weeks 5 days. By that time it was 123,000. I know that hcg doubling time slows in early pregnancy but is it normal that in around 2-3 weeks it tripled? I’m getting worried that it should be way higher because of how high it was at 6 weeks?