confuse

my period was due on the 1/15 which it showed up. however there is nothing coming at all on the pad its been 4 days now abd the only time I see anything is when I pee , I also notice my vein are showing up on my breast which I never notice before I am taking iron tablet so I am wondering if that would be the cause of the more visible veins and the issue with my cycle I have taken pregnancy test which they all say negetive also Ihave notice that I am losing weight.