Baby measures too small for gestational age

I am freaking out. My beautiful baby girl is measuring too small. I have been followed by a specialist throughout my pregnancy beacause they did the Down syndrome test and I was flagged 1 in 10 for it. Which is rare for someone my age. I am 26. The test came back negative ( I did the blood work) but now the doctors are saying that it could be something genetic ( a more rare form of Down syndrome) or an infection. They also found ecogenic bowel in my baby intestines. This is my first baby. I am scared. They are doing about 8 different tests on me. I will get results on wed. Now they will start monitoring me weekly. Possibly hospitalize me. Has anyone had a similar situation? I need to know if they had a healhty baby! Please help!