How can i get on birth control so my periods can be regular i bleed sometimes for a month?

Your doctor...: ...Can certainly prescribe it for you if it is the appropriate course of action.

Get a script: When a woman's periods are irregular, including lasting for a month the way yours do, going on birth control pills can be a great way to manage this. To get on birth control pills a woman will need a prescription. Go get seen at a clinic, and have someone review medical history and get an exam. You can see your doctor or be seen at a clinic such as planned parenthood.