What Causes Delayed Periods With Pain Radiating From Lower Abdomen To Pelvic Region?

hi my name is laura im 24 i misssed my period for 6 weeks and i done pregnancy tests and they showed up negetive im also getting pains down below where its hurting and radiation to my private area and and i do feel sick i have thease pains and i missed my period can u help me i also suffred pcos