Terrified of a miscarriage thanks to PGAL brain.

So I'm currently 4w4d pregnant with a surprise baby. I'm only 4 months PP and I wasn't taking Clomid or anything obviously. When I wad TTC#1 I had 6 misvarriages in a row before having my son. To have my son I had to take Clomid to raise my progesterone levels because my progesterone was so low my RE said it wound be "a miracle" of my body sustained a pregnancy even with progesterone supplements. I'm on progesterone supplements but I'm so terrified it won't be enough and I'm have miscarriage 7. I'm checking for spotting everytime I go to the bathroom. I'm worrying myself sick over every cramp and symptom, or lack thereof. I'm so scared when I go to my first prenatal appointment at 8 weeks that there won't be a heartbeat. I don't know how to turn off the "PGAL brain" (PGAL= pregnant after loss). I want to have the blind optimism that so many women have that a positive test means a baby in ~8 months but I just can't find that confidence. I feel like I'm waiting to miscarry more than I'm waiting to have, a take-home baby if that makesnoon sense. I know of anyone understands how I'm feeling it's other ladies who have been through loss.