So nervous

So my oldest was 5 lbs 14.7 oz born at 41 weeks. My second was 6 lbs 3.3 oz born at 38+4. This baby is already measuring in the 85th percentile (4 lbs 14 oz) at 32 weeks. I'm so nervous. I love my tiny babies and I'm so scared to have a big baby and especially since I'm trying to go natural or at the very least without an epidural. How do I go from 5-6 lb babies up to possibly a 9 lb baby?? Just nervous. I have a birth plan and I hope to stick to it but this scares me.

I also really think my due date is off about a week. My first ultrasound was done at the hospital due to bleeding. A week later, I had one by one of the doctors in my practice. The first one had me at 6+4 and the doctor measured the baby at 8+2. At my second ob appointment, I had a different doctor, who put my due date as the hospital measurements and said he thinks we should go with the first ultrasound. It may only be a 6-7 day difference in the ultrasounds but I think I'm 33 weeks instead of 32. 33 weeks matches better with the last cycle and my positive ovulation test in November.