PREGNANCY SYMPTOMS, LATE PERIOD, BUT NEGATIVE TESTS?!

ok so this is pretty much an update from my last post, im now 3 days late, still having all the early pregnancy symptoms, with major increased nausea every day for most of the day...but still getting all negatives on the home pregnancy tests???!! its driving me crazy!!! i have 2 kids already, so i know all the symptoms, and i do feel pregnant. im nauseas, tired/sleepy every day, milky white discharge a couple times, possible implantation spotting a couple weeks ago, temp is up and down, smelling EVERYTHING and certain smells i normally like are bothersome and make me gag:-/ especially in mornings. pretty much only symptom i dont have is sore breasts. i dont even feel like im about to start my period anytime soon, and im 3 days late, i just dont understand why i keep getting all these negative test results? shouldnt it be showing up by now?