What Causes Recurring Brown Discharge Days After Completion Of Menstruation?

hi, i am 35 and mother of two kids.i had my regular periods on 15th April after 8 days the bleeding stopped but the brown discharge/ residuals kept coming. On 27th april,periods started again and after 8 days, the brown discharge started again.At this time an ultra sound was carried out &the report was normal. On doctor"s advice,Azomax tablet(3 days) & metniv gel were administered. Now after 7 days of gap, the brown discharge/residuals have reappeared. WHAT TO DO ??