period due today but hasn't came yet

Alicia
So today I am supposed to start my period and it's not here yet I took a test but can't quit make out of it's a real faint line or just simply a negative test a couple days ago I had really bad pains in my lower stomach and I have had bad breast/nipple pains something that I have not ever felt before how long would it take for a pregnancy test to be positive cause I know that every woman is different