If you got periods on due dates regardless of flow then chances of pregnancy are poor. Normal cycle length is 26-32 days. Few days up or down are considered as normal. During pregnancy, levels of a hormone called progesterone are high and cause pregnancy symptoms. This hormone is also present in high quantities few days before periods and can mislead for pregnancy. In my opinion, you are not pregnant and your periods are about to come. Wait for your periods for few more days and get pregnancy test if no periods.