When you’re suffering from nasal congestion and fatigue, it can be tough to determine whether you have an ordinary cold or something more serious like influenza (the flu).
In either case, you should get plenty of rest and drink lots of fluids. Over-the-counter products such as decongestants, antihistamines, and pain relievers may relieve symptoms. Antibiotics will not help, because colds and flus are caused by viruses, not bacteria.
Source: The National Institute of Allergy and Infectious Diseases
If you have the flu, prescription drugs can shorten the duration of the illness if taken soon after symptoms appear. Treatment with medication is especially important for people age 65 and older and those with lung disorders, because they are at increased risk for flu complications such as pneumonia or bronchitis. If you fall into one of these categories, you should see a doctor if you suspect the flu.