What do i do now?

I recently started bleeding again after having my period on the 4th. Its the 21st. 2 periods in one month is irregular for me. Its always at the beginning and nothing more. I am on birth control and have been for 2 months but my previous periods were regular and just lighter at the beginning i assumed because the control. Google gave me 3 options:pregnancy, stress, std. I havent been stressed and have had a consistent partner for 10 months. And im on birth control and take it everyday. Ill be calling a doctor but what else should i do to figure out whatsup? My diet isnt bad at all either. The only other health condition i have is anemia.