I have endometriosis and I have terrible periods. Well, my significant other came back from Iraq on Sunday and we had unprotected sex. He did ejaculate inside of me. My period usually comes every 20th-23rd day of the month. I have been off birth control for a year now. My period came on the 25th. I had a light pink discharge for one day before it came followed by almost three days of terrible cramps. Now, I have my period and It's been the worst one since I've stopped taking birth control. I vomitted three times during the week before my period came. I was not ovulating when I had sex, yet my cycle was 4 days late. This cycle was very odd. I'm wondering if I could be pregnant.

It's very doubtful that you are pregnant since you were not ovulating and you did get your period.