I had unprotected sex on the day I ovulated and the day after. I have a regular 28 day cycle like clock work. I got my period, but it only lasted 3 days instead of the usual 7 days, and was much lighter in consistancy than normal. I understand that the unfertilized egg is shed with the lining of the uterus during a period. But, this period was not a usual one for me. I've also heard that a woman can be pregnant but still experience vaginal bleeding that can be mistaken for a period. My concern here it that when I did have unprotected sex during ovulation, it was last month. This month I did not see any signs of ovulation at all. No cervical mucus discharge, no pinching feeling in my ovaries, none of the usual. I have not been under any stress lately. What could be the cause of delay or not ovulating at all? Even though I had a short period last month, if I didn't ovulate this month, could I possibly be pregnant?

Yes pregnancy will cause that. While it may be early, you can try a pregnancy test with the first urine of the morning. If not, wait to see if you have the next period.