I had my anatomy scan today and...21 weeks

Da

Found out i have a subchronic hemorrhage. Has anyone else had one? I have no idea how i got it my doctor said it couldve easily happened just by walking. Im worried about my baby, but im hoping it just goes away.

He weighs 13oz and is in 29th percentile. Also my amniotic fluid was like .3 low he said he wants 10 cm around baby but i only had 9.7..