I Am A Fourth Grade Teacher And There Has Been

I am a fourth grade teacher and there has been a stomach bug going around our school. Last night at 2 a.m I woke up feeling like a rock was sitting in my stomach. I have not thrown up. The pain comes and goes. I thought it was gone about an hour ago and it returned. Sometimes my back hurts when the pain is in my stomach and I do have a headache with it. I don't have a fever and I am not having trouble breathing. Overall I am in excellent health. Last week was an extremely stressful week. Do you think this is just a virus or stress related?