To much fluid around baby and fluid in her kidneys

Im 20 years old and pregnant with my first child. i was sent to see a specialist for a cyst in my right ovaries but during that check up the doctor found fluid in the baby kidneys and to much fluid was surrounding the baby. he told me the baby looked good and everything else seemed normal. he said something about preterm labor and down syndrome which crushed my heart. no one in my family or boyfriend family have any birth defects. i had did blood work before for any birth defects and it came out negative.the cyst i have is not causing any harm to me and baby and is very small..please help i cant stop worrying even though i know my baby girl is fine i can feel it and know my lord and savor would not let this happen