What should I do about my broken fibula?

The number one thing i advise is not too rush back to strenuous activity after a fracture. Let your body heal, the bone will be weak you don't want to re-injure yourself straight away. It take around 6 to 8 weeks for a bone to reform to its original strength, (depending on the severity of the fracture etc.) You are young so you should be back training soon, just don't rush recovery as I said.