Confused

My period started june 25th and ended the 29th... however yesterday and today ive experienced slight cramping in my lower abdomen and lower back as if im on my period or about to be on it. No bleeding is occuring, urine looks and smells normal... idk what it could be. Last time of intercourse was 2 days before start of period and yes, im on birth control pills. Missed a day in first week of june but doubled up the next day as directed (only off thing about june).