I had gotten my period on September 2nd, and had unprotected sex with my boyfriend on the 3rd while i was still on my period. But he did not completely finish inside me. Recently on September 23rd i experienced some bleeding and it was extremely heavy. I have been exercising recently and heard that it could change when i got my period. Could i be pregnant and experienced implantation bleeding or just had an early period. I'm really worried because i was definately not planning on getting pregnant, PLEASE HELP!