Why have I started bleeding again? My period just ended a week ago!
If there is a chance you could be pregnant you should check a urine pregnancy test, pregnancy can be one of the most common causes of new-onset irregular bleeding. If that is negative, then you need a physical exam, lab work, and likely an ultrasound to determine why you are having irregular bleeding, numerous causes including fibroids, polyps, hormonal disorders, and bleeding disorders can cause abnormal bleeding.