If you have flu-like symptoms, but no fever, you might suspect that you have a cold. It is not always easy to tell the difference, and a cold can even cause you to have a mild fever.
In general, all symptoms are worse when you have the flu. You are also more likely to have congestion, a runny nose, a cough, a sore throat, or sneezing with the flu. Exhaustion is also characteristic of the flu, and is not nearly as extreme when you have a cold.