What Causes A Delayed Menstrual Period?

I am 42 (just),my husband has had a vasectomy. Periods have always been very regular every 28-30 days and I also have endometriosis. But my period is 9 days overdue, my mother and sister went in to an early menopause, could this be the case? The last few periods were a little lighter, but very painful. Just need an answer as am starting to worry.

Thanks, Gill