I am just wondering how accurate are pregnancy tests, i know they say they are 99% accurate but i am just not sure. I have done 2 pregnancy tests over 1 week and they both say negative. I am 10 days overdue on period (42 days since last period), nauseated and have tender breasts and i really think i am pregnant. I know i should just go to the doctor but dont want to risk being disappointed. Has this happened to anyone else and then found out they were still pregnant.