Its hard to tell until you actually test. For mw, I knew I was pregnant, I tested and the test was negative. The very next day, I got my cycle and it lasted 4 days, I was at the doctor and they tested me for pregnancy before I started BC, and the test wad positive. Even my blood test were positive. I had a "period" while pregnant. So I would test the day of your expected period. My nipples hurt, I was starving, and I felt sick all the time. Best of luck!