Rubella Immunity

Emily • 25 / Married / Mama to Maddox (2009) and soon, Elijah (2016) too.
So my doctor called today, she never calls me first unless I email her about my Hyperemesis or something like that. She said I have little to no immunity against Rubella. She made it seem extremely serious that I avoid kids and kid places such as day cares/chuckeecheese, busy places full of people and confined areas (I'm assuming like planes or small rooms with strangers). 
I read online that it can be dangerous to the baby, causing stillbirth, as well as serious birth defects. I also read that the sickness isn't that common because most children were vaccinated as a part of their school booster shots. But still, I don't see why she would call me, be very stern and serious if it wasn't something to be something worried about. 
What does this mean? Anyone else ever go through this? Am I freaking out for no reason?