I just had my period one week ago and now i am bleeding again. my stomach hurts a little bit on the lower right side. what would be the problem?

Ovarian cyst: Abnormal uterine bleeding may be caused by many things, such as anovulation or failure of an egg to be released by the ovary at the right time which can cause an ovarian cyst, pregnancy, miscarriage, hormone imbalance, and infection. I would seek medical attention to make sure you are not pregnant, and now miscarrying. This can be checked with a blood test or an ultrasound.