Christian,
I have three absolutely normal, beautiful children: Jessica, Samantha and Coulson. I measured small while carrying all three of them and worried a bit, especially with the first, but they were born perfectly normal in size. Women carry according to their genetics. My mother also carried small and felt a lot of anxiety with her first child -- my brother -- who today is six-feet-two-inches tall!
If your tests to date were normal, then you have nothing to worry about. After looking at my son, Coulson's sonogram, one doctor said that he was bald as a bowling ball -- not a stitch of hair on his little head. Two weeks later, he was born with a FULL head of hair. And to this day, he looks twice his age because of his thick, beautiful hair.
The bottom line is that children are resilent and take from their mother what they need. More than one doctor has said that children are parasites, but I find that comparison unsentimental. Children are gifts from God, and you're about to experience the most JOY you'll ever feel in your life.
Best,
