Okay so for the last month I've been having unprotected sex with my boyfriend, I'm suppose to have my period on the 25 but I ended up getting it on the 19. It started off kinda wierd, I was spotting very lighty for two days, a brown discharge, I was bleeding for two days but very lighty something my period never does. Its been a week & I  have been experiencing light spotting. My period never does this, its always on time & it never changes its flow. Could I be pregnant? HELP