What am I to do? 2 weeks late.

Hello! My period was suppose to start 3/17 and it hasn't came. It took a test and it came out negative Like last week , my friend said it was to early. It will be 3 weeks since I had sex and it will be 2 weeks since my period been missing tomorrow. Yes I have gotten nauseated , my nipples have been little tender for a week or some weeks now , my white discharge has slowed down and I have been cramping like my period is coming and its nothing but white discharge. My period was all out of wack 2012 and 2013 , and it finally got on track and would come 2 days early or even a day early. I haven't miss a period is a very long time. Can anyone help. Also I got pregnant before had a MC at 5 weeks didn't get a positive till 4 weeks on a test. I haven't been stress I have been so happy. Can anyone help?!!