What Causes Nausea, Vomiting And Headaches With Delayed Periods?

Last month, I had a very short light period. Over the past six weeks I've had nausea, vomiting, headaches, frequent urination, nose bleeds, cramping, bloating, sore tender and heavy breasts, the veins in my breasts have been very visible. I thought I was pregnant. My period was supposed to begin on the 16th of this month .