I am 14 days late on my menstral cycle. I have been stressed with things in my life but I have had this stress before and my period always starts on time! Often times early.. My period usually last longer from stress. I have headaches, minor cramping, no sore breast, but a little nausea, and not much eating. I took a UPT on day 12 and it came back negative. What's wrong with me?