Depending on the type of pneumonia you got… community acquired pneumonia is mainly caused by the bacteria Streptococcus pneumoniae (I’m studying this bug as a graduate student). Even though there are two vaccines out, there’s still a 5-15% colonization (where you don’t even know you have it, and your body clears it over time) in the adult populace at any time. Children have up to 50% colonization rate depending on the age group… with children under 5 being the most colonized. Usually only children, elderly and immune-compromised people may get disease after being colonized. You can probably thank your burned out condition for compromising your immune system. Hopefully the antibiotics will kick it in the ass.