Hi. My last period was on 28th September which lasted up until 1st October. My estimated fertile days were 7th-13th October. My estimated ovulation date was on the 12th. I had intercourse on the 7th, 9th and 10th of October, without a condom, the first two times, the pull-out method was used and the third time, the guy ejaculated inside me. My expected period was supposed to be on 26th October, my average cycle is 28 days. I am now supposedly 4 days late. On the first day of my expected period, I had brown discharge which stopped after a couple of hours. I have had nausea, fatigue, cramps, sometimes lower back pains, headache, flu-like symtoms and abdominal pain. I also feel 'twinges' in my stomach that I can't explain. Is it possible I may be pregnant?