Itchy And Sore Nipples, Heartburn, Constant Headache,late On Period. Took 4 Tests,all Are Negative. Treatment?

i am three days late on my period, my boyfriend and i are trying to conceive. I have itchy and sore nipples , heartburn , a constant headache for a week and half now. I m more tired than usual but can t seem to have a good night s sleep. I was nauseas, but that subsided. I feel cramping, as though I am about to start my period, but there is nothing. Ive taken 4 tests, all have come back negative.