Could Early Menstruation Be The Symptom Of Pregnancy?

Hello, I have a question! A month ago I had my IUD removed a week after I had unprotected sex! He used pull out method though! My next period was suppose to start on March 13th but instead it started March 9th just a day after I did that! My only concern is can I possibly be pregnant? We had sex more than once that night! Now I m getting nausea and few cramping! Please help!