Sir Good Morning Some Times Get Reguller Periods Nd Some

Sir Good morning some times get reguller periods nd some times accur irreguler periods to me nd normal bleeding this month my date completed after 8 days I get period .but these 8 days I have vomit sensation bback pain nd some symtoms but I can I get period .actually every time I get period before 10 days back ,stomach, chest,leg painsare their but this month I has some symtoms of pregnancy .why like this? Pls help me doctor. I completed my marriage 5 yrs .