I normally get my period around the end of the month, it was on time end of august but its come again on the 10/09. i'm experiencing terrible cramping and feeling nauseous. ?

Hormone imbalance: Reasons for irregularity include weight gain or loss, breastfeeding, alcohol use, eating disorders, marked emotional stress, endometriosis, uterine fibroids, cervical polyps, polycystic ovarian syndrome, excessive exercise & pregnancy. When a girl has just started menstruating & around the time of menopause periods can be irregular.