What does a flu vaccine protect me against? what does it not protect me against?

Influenza: It decreases the risk of influenza (the common cold), which is a viral infection, but the flu shot will not protect you against bacterial or fungal infections.

The predicted flu: Each year a prediction of the most likely flu viruses to occur the following year is made and the vaccine is created to combat them. Sometimes the get it right and sometimes not so much. It is worth vaccinating because there is somtime cross coverage even if it isn't exactly right.