NEW YORK (CBSNewYork) -- A cold, or a cough. Maybe some unusual pains. Nothing serious, right?

Actually, it was serious for a few high-profile people recently who seemingly ignored the signs of serious illness.

CBS2's Dr. Max Gomez has more on the symptoms you should always pay attention to.

It's a fine line between listening to your body's warning signs and hypochondria. A nicer term is the "worried well," people who think every headache is a brain tumor. It rarely is, but there are signs that something serious is going on that you shouldn't ignore.

CBS This Morning anchor Norah O'Donnell's spring break vacation was cut short this week when she landed in the emergency room and had an appendectomy.

"Her husband, Jeff, says she played tennis for two hours in intense pain because she thought it was a little gas," Gayle King said.

O'Donnell's reaction was not that unusual. According to Mount Sinai Emergency Medicine physician Dr. Jim Tsung, who says often people will ignore symptoms, hoping they will go away or confuse them for something less serious.

"We have people who come in at the slightest drop of a pin and then we also have people who are having a heart attack and show up when it's almost too late," Tsung said.

After a month away from her talk show, "The View," Whoopi Goldberg is finally on the mend from a serious bout of pneumonia.

"So if it's a cold and it's lingering on and so, certainly, if the cough is getting worse, their having difficulty breathing, that's certainly a reason to seek medical attention," Tsung said.

MORE: What You Need To Know About Heart Disease And Diagnosing The Symptoms

Goldberg revealed her pneumonia became sepsis, an extreme immune system reaction to an infection.

You may remember Jim Henson of "The Muppets," and most recently actress Kim Porter. They both died as a result of sepsis.

Almost any infection could become sepsis. Signs include fever, rapid heart rate, shortness of breath and disorientation. Skin infections can also be serious. Any skin lesion that gets hot, firm and red, with streaks running towards the heart, should be seen by a doctor.

Those bacterial infections can go from unpleasant to deadly in just hours. Don't wait for a doctor's appointment. Get to the ER or urgent care.

Unless pain is excruciating you can usually wait to see if it gets better. If it doesn't, it's doctor time. And, of course, in the cases of chest pains, shortness of breath, sudden one-sided paralysis or slurred speech get to the hospital.