Fifth disease exposure?

I'm 15 weeks and a few days and I'm a school teacher. My school nurse told me today that a child in the school had fifth disease and she needed to let me know. I'm trying not to freak out but it's hard. I just left my OB where they did a blood test. I don't teach or work with this child but I've been in the child's room once, helping a different child. I also work daily with the infected child's sibling. I have no idea what my risk of exposure is. Has anyone dealt with this before? Has anyone gotten this disease early in the fourth month and their baby been OK? I'm really scared.