Could I be pregnant.

Kathleen • 28 years old, medical assistant, married to my wonderful husband and we have a 7 year old little boy who is my world.
My lower stomach and up above my pelvic region is hard. I had a period on the 26th very light one and right before that I had nausea and sore breast. My stomach had been like this for about 1 1/2weeks and I'm going to the bathroom normal could this be a sign I'm pregnant even though the test come up negative.