What Causes Delayed Periods For Over A Week, Abdominal Cramps And A Lot More Discharge Than Usual?

Hi. I have a regular menstrual cycle, it s usually only 1-2 days off if anything. However, this month I am 8 days late! I took a pregnancy test yesterday which turned up negative. I have mild cramping, very similar to when my period is about to start but no period. I have more discharge than usual, it s very watery and feel as if my period has come but does not show up. My breasts feel very sore and heavy, and I am starting to form stretch marks on them. They appear very pointy, and my areolas seem larger than usual. If my period does not show in the next 4 days, I will be 2 weeks late.