Abdominal pain.

Im currently on cd52 and 27 dpo i have had loads of bfn (although yesterdays test was debatable and even people on here said they thought they could see a line and when i came back to it this morning there was definatley a line but not sure if it was an evap) and no sign of af. I started with pains in my lower abdoman yesterday that feel nothing like period pains and they are have gradually got worse and now they are unbearable. Has anybody else experienced anything like this and what was it.