ok... i am waaay late on my period i have had unprotected sex since my last period is it possible im pregnant? i have taken 4 hp tests and they all come up negative is it still possible to be pregnant? i keep getting headaches my back is hurting and i feel tired all the time i havent really noticed much in weight gain but i am a lil over weight so it could be hard to tell. i eat a little more than i use to and i feel a little sick at times. do you think i could still be pregnant?