hi your condition is called polymenorrhoea. because it is a recent event and you are sexually active   first i have to rule out prgnancy and related complications with blood bhcg deal with it if positive. .if negative it could be because of exibition hormonepills you are  taking for contraceptionor because of hormonal problem like thyrotoxicosis.. if no it could be pelvic infection  which can be ruled out by physical examination culture and treated. if infection is not there and there is no pathology it is called dub which could be because of stress life style etc  which can be symptomatically treated and followed up. hope the answer is sufficient. kindly go for a gynaec check up most of the time it will be simple cause. diagnosis is always by elimination with logic and objective evidence