It's too bad that basic immunology isn't taught in high school. I really wish more people knew what getting a common cold or flu really means and especially what their symptoms mean.
First, there are pathogens EVERYWHERE. The minute one leaves the shower, he or she is covered with bacteria. Everything is covered with germs, germs, and more germs. With that being said, why do people only tend to get sick only a couple times of year? Without an immune system, the body would be sick all of the time; however thanks to an effective immune system, the body constantly and successfully battles the bugs. BUT why does our immune system fail every now and again? When the body is treated badly or neglected, the immune system can't function optimally. There really aren't superbugs going around making everyone sick, just our bodies get run-down and we are taken over by a simple germ that's be in our lives for years.
Secondly, when sickness does arise, try to sit back and take it easy as the body fights. Please don't think of sickness symptoms as evil; they really do happen for a reason. Here are the basic cold/flu symptoms and why they are important:
Cough - The body is coughing to try and get rid of the pathogens and/or dead cells and pathogens.
Excess mucous - Mucous protects the body. During sickness the body will make more mucous to protect itself. Also, the body using mucous to get rid of pathogens and/or dead cells and pathogens.
Tired - The body burns more energy to fight the sickness. The body will feel more tired as more energy is lost. The body needs to focus its energy on fighting, so rest is key.
Fever - The body raises its temperature to denature the bad proteins of the pathogens.
Thirdly, when the common cold and flu symptoms are suppressed or covered-up, the immune system will have a harder time of overcoming the sickness as it doesn't have its regular mechanisms (fever, cough, etc.) to put up a proper fight.