How severe are your symptoms?

“Both the common cold and influenza can include upper respiratory symptoms such as sinus congestion, runny nose, sore throat, and cough, as well as systemic symptoms including fever,” says Clifford Swap, MD, an emergency medicine specialist at Kaiser Permanente in San Diego, CA. However, flu symptoms tend to come on quickly and be more severe than in the common cold. Here’s how you can tell the difference between the flu and a cold.

Are you achy?

You may notice some mild aches and pains with a cold. When they’re flu symptoms the pain is much greater, points out Dr. Swap. If you have the flu, your muscles and joints will hurt. The pain will often be felt in your head, back, and legs. It could even be painful to move.

Are you feverish?

While you may see the thermometer climb up to 99 or so, it is rare to have a high fever with a cold. With the flu, however, you usually (though not always) see a fever, often in the 100 to 102 range, points out the Mayo Clinic. Keep in mind that number can be higher, especially in young children. Don’t be surprised if the fever lasts several days. Even though it feels awful, remember that fevers are your body’s way of fighting off the infection. You can always try one of these natural flu remedies to quell those pesky symptoms.

Are you having chills and sweats?

You’ll sometimes get chills and sweats with a cold, points out Dr. Swap. They are common symptoms of the flu, however. Sometimes body aches can cause chills. Sometimes a fever can cause chills as well, though the flu may cause chills even without a fever.

Are you feeling weak and fatigued?

Another question to ask yourself when determining if it’s the flu or a cold? Having a cold can sometimes knock you out, or make you feel a little less chipper than usual. But with a cold, that symptom generally lasts just a few days. Flu symptoms, on the other hand, can last a few weeks, according to experts at the Mayo Clinic. You’re also much more likely to be exhausted when you have the flu—for example, sleeping for the most of the day—than you are with a cold. Here are some more medical conditions that could leave you exhausted.

How’s your tummy?

While not all strains of the virus will give you stomach trouble like vomiting, diarrhea, or stomach cramps, these still might be signs of the flu, points out Dr. Swap. If you find yourself running to the toilet, it’s most likely not a typical upper respiratory cold. And be sure to avoid these foods that can make the flu worse.

Think it’s the flu? Here’s what to do

If you think you have the flu, what to do next: Hole up until those flu symptoms pass, or make an emergency doctor’s appointment? “If you are not in a high-risk group and your symptoms are mild, you do not need to see your doctor or be treated with anti-viral medications,” says Dr. Swap. High-risk groups include young children, people age 65 and older, pregnant women, and those with certain medical conditions. These groups are at an increased risk of developing flu-related complications, like pneumonia. “If however, you are having severe symptoms or are at high risk, consideration should be given to treating with anti-virals [such as Tamiflu or Relenza], as some studies indicate they may shorten duration or severity of symptoms,” Dr. Swap adds. Baloxavir is a newly approved antiviral flu medication given in a single dose. You should also see a doctor if you develop any dangerous flu warning signs, which the Centers for Disease Control and Prevention categorizes as difficulty breathing or shortness of breath, pain or pressure in the chest or abdomen, sudden dizziness, confusion, severe or persistent vomiting, or recurring signs of the flu. For children, a doctor should also be consulted if they are not drinking enough fluids, become dehydrated, or become listless. Now learn how you might be messing up your flu shot.

And here’s what NOT to do

If you think it’s the flu, avoid contact with others. Don’t try to power through your day at work—you’ll only risk exposing your coworkers and others you come in contact with. If you must go out, for instance, to see a doctor, wear a face mask. “Influenza is highly contagious, and often debilitating and even deadly. It is estimated to cost the United States $10.4 billion annually in missed work and medical care. When you feel horrible it may not be foremost on your mind to prevent transmission but it is important nonetheless,” Dr. Swap cautious.

How to prevent the flu

Remember, Dr. Swap says, “the best thing you can do to help prevent transmission is to get your flu shot!” Get the shot and get it early. Flu season typically starts in October and ends in March with peak season in February, according to the Centers for Disease Control and Prevention. The shot can be available as early as late summer. To prevent you and others from getting sick, follow these 14 anti-germ etiquette rules for flu season.