4. Fever
You may feel tired and achy and have a cough, but once you touch your forehead and feel the warmth, you may be in denial about having the flu. In fact, some people who experience nausea might think they are experiencing food poisoning until a fever develops, then it is clear what is happening.
If you pull the thermometer from your mouth and see if it is 100 degrees F or 38 degrees C, you can be sure you have a fever. A fever is a sign that your body is fighting the flu, and is not worrisome in and of itself unless it reaches 103 F.
Extremely high fever, especially in young children, is a reason to seek medical care, but in cases of mild fever, there is no cause for alarm. You can allow the body to fight it out, or if you find it is unbearable, take some ibuprofen or another fever reducer.