My daughter is 19 and works in customer service. She has had flu like symptoms along with fever 3 times in the last month and it only last 12-24 hours. She isnt able to keep anything down during that time and has a terrible headache. She is not pregnant and is not on birth control, she has had her tonsils out and is overall active and healthy. She doesnt eat alot, she is 5'9 and weighs 140 lbs.