My period usually starts on late 20 of each month, today is the 27th and i'm on my period. last month i believe i was on my period around 24-26? i'm not sure but usually my periods are around the late 20s. I get really bad cramps everytime. i had unprotected sex for about less than 8 mins. he claims nothing came out. i'm worried i might be pregnant. could it be just my rag being lil late or implantation bleeding?