Not sure if you're coming down with a cold, the flu or just one of those 24-hour flu bugs that leaves you feeling nauseated?

Seasonal flu often includes a fever above 38.5 C for two to four days. (Ng Han Guan/Associated Press)Well, first off, that 24-hour bug isn't the flu at all. If it has kicked you in the gut, you probably have viral gastroenteritis — an infection caused by a variety of viruses that results in vomiting or diarrhea. It is often called the "stomach flu," even though it's not caused by any of the influenza viruses.

A cold and the flu share some of the same symptoms. But even a bad cold is pretty mild, compared to a bout with the flu.

No pill or herb will get rid of either — each is caused by viruses and antibiotics, herbal remedies and homeopathic medicines are useless against them. You can take things that might ease your symptoms, but there is no cure. Your illness will have to run its course.

A cold usually comes on gradually — over the course of a day or two. Generally, it leaves you feeling tired, sneezing, coughing and plagued by a running nose. You often don't have a fever, but when you do, it's only slightly higher than normal. Colds usually last three to four days, but can hang around for 10 days to two weeks.

Flu, on the other hand, comes on suddenly and hits hard. You will feel weak and tired and you could run a fever as high as 40 C. Your muscles and joints will probably ache, you will feel chilled and could have a severe headache and sore throat. Getting off the couch or out of bed will be a chore. The fever may last three to five days, but you could feel weak and tired for two to three weeks.

The following chart illustrates the major differences between cold and flu symptoms:

Signs & symptoms	Cold	Flu
Fever	Occasional	Often above 38.5 C for 2-4 days
Headache	Frequent, but not severe	Prominent and often severe
Aches/pains	Slight	Often severe
Fatigue/weakness	Mild	Can last 2-3 weeks
Extreme exhaustion	Never	Early and prominent
Stuffy nose	Common	Occasional
Sore throat	Common	Occasional
Cough	Hacking	Can be severe
Chest discomfort	Mild to moderate	Common, can become severe
Onset	Gradual (develops over a day or two)	Sudden (within a few hours)
Cause	200 strains of cold virus	3 strains of influenza virus