What Causes Abdominal Bloating, Nausea And Headache After Having Unsafe Sex?

My question is regarding the possibility of pregnancy. I am on birth control however am prone to missing pills or not taking pills at the same time each day. Last month I had unprotected sex a few days after coming off the inactive pills, the guy definitely did not ejaculate inside of me. I had some spotting a week before my expected period, however my period came the following week only one day late. I had severe cramping throughout and a week later still have abdominal pain, headaches, feelings of nausea, bloating and flatulence. Could I be pregnant?