Flu is different from a cold. The flu usually comes on suddenly. Getting vaccinated before flu activity begins helps protect you once the flu season starts. Page ContentInfants, young children, seniors, pregnant women and those who suffer from chronic respiratory illnesses such as asthma and COPD are considered at increased risk."If you typically come into contact with any members of these populations and are feeling under-the-weather, it's important to ask yourself whether you might have the flu, so that you can help avoid spreading the virus and endangering others," says Peterson Halvorson, M.D., a board-certified Family Medicine physician at Kelsey-Seybold.Here are some symptoms of flu according to Kelsey-Seybold physicians:Aches Chills Cough Fatigue Fever Nasal congestion Sore throat Vomiting and/or diarrhea It's important to note that not everyone who has the flu will have all of the symptoms listed. Some people with the virus don't even get a fever.If you are considered a member of a high-risk group or worried by the severity of your illness, make an appointment with your Kelsey-Seybold primary care doctor by calling our 24/7 Contact Center at 713-442-0427 or schedule online with AppointmentsNOW. Your doctor can determine if you have the flu and whether additional treatment, such as antiviral medication, is necessary.