I am so confused. My husband and I had intercourse my most fertile days because we are trying to get pregnant. I have taken about 5 HPT, and 3 came back positive, 2 negative. I had blood work done at one of the doctor's offices in the building I work at, came back negative. I am 2 days late. Only symptom's I'm having are VERY sore breasts and extremely tired. What could be happening?