How can you tell if you have the flu or just a bad cold?

Influenza tests.: Tests specific to influenza a/b can be performed at your doctor's office.

Cold vs Flu symptoms: Flu symptoms may include fever, sore throat, cough, achiness all over, headache, chills, feeling tired, nasal congestion, nausea, vomiting or diarrhea. Colds are usually much milder than the flu and often lead to a runny nose. Colds don’t usually lead to serious complications (i.e., pneumonia).