My first day of my last period was January 10th, 2013 for 7 days (Normal) and my cycle is normally every 24-26 days. I started spotting on January 28th but only when I wiped and not every time (only did this a few times in a 2 day span). I thought this was the start of my period but it never stated up. Now I am a total of 16 days late with my period being a no show. I have take a urine test the first week and it was negative, took one again tonight and negative again. My period is never late like this...ever. Since they are negative should I assume I'm not pregnant and why so late? I'm not stressed so I'm unsure what is going on. Any advice?