I'm so very sorry to read of your loss. It is heartbreaking for you and your family.
Your HcG levels alone are excellent - as are your P4 levels - certainly enough to sustain a pg.
There are a few things that can be done for future pregnancies to allay recurrent miscarriage (I'm sorry that word sounds so clinical with what you are currently going through)
I would suggest that you go to see a fertility specialist (rather than your normal GP). Ask them to do karyotyping and immunology testing. Karyotyping requires a DNA sample from both you and your partner (blood or a cell sample from your mouth), immunology is a blood test for you. Suggest you ask them to check for (amongst anything else they think necessary)¦. ANAs, ACAs , MTHFR, NK cells and homocysteine levels.
After a couple of early m/c's - I was found to have a low level ACA antibodies (blood clotting when it shouldn't). This is a known cause of recurrent miscarriage. After diagnosis I injected Clexane (a blood thinner) every day of my pregnancy from transfer of embryos (we were IVF) until 34 weeks pregnancy. We finally got our take home baby.
Thinking of you