Pneumonia is an infection that inflames the air sacs in one or both lungs. The air sacs may fill with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing.
Anemia happens when you do not have enough red blood cells. The cells travel with iron and hemoglobin, which is a protein that helps carry oxygen through the bloodstream to your organs all through the body.
The key symptoms of depression include persistent sadness or low mood, loss of interests of pleasure, and fatigue or low energy. At least one of these symptoms occur most days, most of the time for at least two weeks.