Bleeding, cramping with a dead odour

Patient: Hi im 20 yrs old i started BC six months ago everything was fine until now. i been bleeding for two months now and sometime with a pinkish,sometime brownish gray discharge that have a dead smell to it..i went to the doctor and got a pep smear and blood test everthing came back negative. i have no STD’s or BV or yeast infection..i change BC last month but the samething is till happen. for the past week i been cramping and bleeding with a dead odour