I need advice it's an emergency

It's been since October 9 when I got my birth control, depo shot, in. It lasts for 3 months. then the third month came,my period wouldn't stop. It kept going into the next month and now it's the third month. My period will stop and spot brown then go into another period even heavier than the last. The cramps and pains got severely worse too. Could there be something internally wrong?