Pregnant

Sorry, long post. Long story short. Boyfriend finished in me. No birth control. No condoms. Nothing. It was like 5 days before my period. I got my period but it is much shorter, lighter, and less painful from my normal cycle. I usually last 4 to 5 days and I only lasted 3 days. My question is: could I be pregnant and when can I take a test? Like I said, no contreceptive used. 5 days before period. Is it possible?