It started with the achy muscles and quickly escalated to a runny nose, fever, cough, and chills. You have the flu.

At first, you might think to treat it like a bad cold — but the flu is different. Doctors explain five things you shouldn't do when you're sick with the flu.

1. Don't take cough medicine.
The flu can cause a nasty cough that leaves you exhausted and sore. But over-the-counter cough medicines aren’t effective at quashing coughing, doctors say.

That’s because the doses of cough suppressants in these medications are too low, according to Dr. Richard Irwin, a professor of medicine at the University of Massachusetts Medical School in Worcester, Massachusetts, and chairman of the cough guidelines committee for the American College of Chest Physicians (ACCP).

“Typically, they don’t work,” Whitley-Williams agreed.

Cough medicines that contain opioids like codeine should never be given to children, the Food and Drug Administration warned in early January.

“Children should not take any cough or cold medications,” said Dr. Nasia Safdar, medical director of infection control at the University of Wisconsin Health. “They are not beneficial and might be harmful.”

Also, whatever you do, don't mix products containing acetaminophen like Tylenol or Nyquil or Theraflu. The recommended daily dosage — for the entire 24 hours — is no more than 4,000 milligrams (mg). Going over that dosage just little can cause severe liver damage.

2. Don’t take antibiotics.
A virus causes the flu. Only antiviral medications treat viruses. Antibiotics treat bacterial infections.

“Influenza is a virus. It is not cured or treated by typical antibiotics,” said Dr. Patricia Whitley-Williams, division chief of allergy, immunology, and infectious disease in pediatrics at Rutgers Robert Wood Johnson Medical School.

Antiviral prescription drugs like Tamiflu do treat the flu, although doctors generally only prescribe it to people with compromised immune systems or who are more susceptible to illness, such as young children, older adults, or pregnant women.

“Those are the groups that should seek attention,” said Safdar. Tamiflu works best when given within a day or so of the first symptoms, so don't wait to see the doctor if a high-risk loved one shows signs.

3. Don’t lie down.
This may be the most difficult! High fever. Aches. Chills. All you have strength to do is put your head on a pillow. Resting during the flu is very important, but lying down makes it harder on the lungs. Lying upright will make it easier to clear the lungs.

“It feels better to have your head up and it makes it easier to breathe,” said Whitley Williams.

Safdar said sitting up right stops the congestion from trickling down the back of the throat and causing a tickling feeling. Which leads to ... more coughing.

4. Don’t give children aspirin.
When the fever hits it can cause a headache and people desperate for relief might try aspirin. But aspirin, and other drugs called salicylates, can cause a serious complication in children under 18 known as Reye’s syndrome. This can lead to problems with the liver and brain.

Whitely-Williams recommends acetaminophen or ibuprofen for reducing fever. But be very careful about reading labels of any over-the-counter or prescription medications you take, especially if you're combining medications — overdoses can lead to serious complications.

As for adults taking aspirin or other fever reducers, a 2014 study using math projections suggested it may actually make the infection last longer and increase your risk of spreading the infection.

"An individual whose fever has been reduced is likely to feel better and is therefore more likely to interact with others," the researchers from McMaster University in Ontario wrote. "In addition, fever suppression may increase both the rate and duration of viral shedding, further increasing the pathogen's transmission rate."

5. Don’t drink a hot toddy.
While alcohol makes people feel drowsy, it doesn’t lead to good sleep and can contribute to dehydration.

Resting up and staying hydrated are both needed to help people recover from the flu. What more, booze can make people feel worse.

“Flu can often make people feel very sick and that can include making people feel very delirious and something that can affect your thinking (like alcohol) is not recommended,” said Safdar.

6. Don’t take a cold shower to reduce fever.
When trying to reduce their fevers some people take cold showers or an ice bath. But that has the opposite effect.

“Do not use an ice bath or cold. It will make the fever go up,” said Whitley-Williams. “Sponge down in lukewarm water."

Tepid water actually helps break fevers.

7. Don’t go to work.
“It is so important that you stay home and get rest and try to get over the flu. Otherwise when you go to work you are exposing all your coworkers to influenza,” said Whitley-Williams. “You are putting people are risk.”

The Centers for Disease Control and Prevention recommends that people do not go to work until they have been fever free for 24 hours without the use of anti-fever medications, said Safdar.