Sharp pain

Ok so, my AF is over a week late. I have taken three tests..one before it was due, one two days after it was due, and yesterday. All three were negative, and it seems as if each day the discomfort in my lower abdomen is getting worse. It started off as maybe just an irritating pain but now it hurts to lay a certain way or at time to even breath.  Has anyone else experienced this with a late period? Any advice?