Two days late and a negative pregnancy test

Caroline
So, my period is two days late and this morning I took a First Response 6 days sooner test and it still came back negative. Has anyone else had this happen and then find out later that they indeed are pregnant? 
My symptoms are hard to differentiate because pregnancy and PMS symptoms feel similar. My breasts are extremely sore. I have a lot of cervical mucus so I keep thinking its here and then it's not, haha. I'm extremely exhausted. What do you all think?