26weeks polyhydramnious?

So I am down to every two week appointments now. Today during my sonogram, the tech noticed a lil extra fluid in baby Bs sac. She put in her notes that "stomach never filled during exam." They referred me to a specialist for next Monday. I'm not freaking out but I'm anxious n worried that something is now wrong with my baby. This term polyhydramnious- any moms have this issue? What does it mean? Google never helps!!! Thanks 🙏🏻