QUESTION!

Em
Ladies I have a question... 
if I'm not on my period I have discharge. Like the moment my period stops I have discharge all month until my period rolls back around. 
I had my birth control (Mireya) taken out in May and my doctor did a swab to see if I had an infection that would maybe cause the discharge and there was no infection so I'm wondering what it might be?! 
Anyone have any idea?!