Just Had 4 Periods In A Month, Had 3-4 Days

Just had 4 periods in a month, had 3-4 days between each one . Started Aug 22-27, then again sept 1-8, then sept 12-19, and started again the 21st. I am sexually active and not on birth control, went to the ob and he put me on birth control pills but they made me feel sick and dizzy so stopped taking them . Boobs have gotten bigger & my stomach has gotten bigger but haven't taken a test . I have no idea what it could be ??