Varicella-zoster virus (chickenpox)while pregnant

Hello,

I’m 24 years old and I just turned 10 weeks with my second baby. I just had the first set of routine labs done aka blood test that tested for lots of routine things during early pregnancy and my blood test showed that I don’t have the antibody for VZV. Which is strange because I’ve been vaccinated as a kid.. so wouldn’t that mean I shouldn’t get it as an adult? This is scary news to me because I’ve seen there are serious complications when pregnant! Like birth defects, mother mortality goes scary high… has anyone else had this while pregnant?