i am now 12 days past due for my period. i am not on any type of birth control and have been trying to concieve. my lmp was april 8th and there is no sigh of it coming anytime soon. ive taken three pregnancy tests, two were very faint, questionable positives and one was bluntly negitive. i have been nauseas, had lower back pain, headaches and slightly sore breasts the past week. am i pregnant or is something else wrong?