Chicken pox

I am 15 weeks and 5 days along. I just got my blood test results back from my doctor and it turns out I am not immune to the chicken pox even though I had them and the shot as a child. The doctor said that the immunity can wear off over time?? Which I had no idea and I know how bad chicken pox can be while growing a baby. So, as a already worrier- I am freaking out. I work in a gym so I’m sure there are germs and viruses everywhere. I don’t even want to leave my house until this baby is born! Has any one else been in this situation?