Help me :(

Amy Jo • 29, married to the love of my life, mommy to an amazing baby boy 8•11•15, now expecting #2 in April ❤️
I started my period September 30th my cycles have always run 28 days spot on. I still have not started and I've taken pregnancy tests and they all say bfn :(. How long should it take to come up positive? And how long should I wait to call my Dr?