Definitely! When my kid gets a headache, it's a brain tumor. When my child gets a fever or stomachache, it's leukemia. My youngest (kindergarten) wasn't eating her lunch at school and said her stomach hurt in the morning. This happened a lot, continually, until I figured out she was nervous and scared of one of the lunchroom helpers. Yes, I definitely freak when my kids don't feel normal. There is a family we know well whose little boy has neuroblastoma, and I think that contributes to some of my anxiety over sick kids.