CMV infection

Okay so I'm 30 weeks pregnant with boy and girl twins. At my like 25 week ultrasound at the dr they noticed the girl was growing smaller than the boy and they sent me into the hospital to be admitted and I had to stay overnight. They monitored the babies and I had a big ultrasound the next morning and they just couldn't figure out why the girl was smaller. Now, they took a bunch of blood test and my blood came back positive for a CMV infection. My dr thinks this may be why the girl is growing smaller, but the only way to know for sure if she has this infection is if I get the amniocentesis test. I'm really worried about getting that test done but I want to know if my baby girl is sick with this or not 😔 any thoughts and has anyone else had this infection before while pregnant?