Help, so confused!

So I had a chemical last month and just got my BFP. I'm in shock it happened next cycle, and very worried. My doctor had me come in for labs, and it was exactly 4 weeks based on when I know I ovulated. My HCG was 552. My progesterone was borderline at 14 so they started me on oral prometrium. He didn't say anything about the HCG level though and I'm wondering if it's ok? I know doubling time is what matters and I will go back for labs Monday. But is 552 decent for 4 weeks or should I be concerned?