I have the flu and i am wondering what the chances of getting pneumonia or bronchitis because of the flu rare?

It's possible: Influenza itself can cause an inflammation of the lungs that shows up on xrays, which may be called "pneumonia". It can also injure the cells lining the airways, allowing for a stapylococcal (classically) or other bacteria to infect the lungs. These can be fairly severe processes and may require hospitalization or even ICU care. However this is fairly uncommon.