Help!

Chambers
So I took three ovulation tests (dipped them one by one) and they all had a very visible test line show and then disappear minutes later. I have been obvulating for about four days now according to the clear blue digital ovulation tests. And today I've really been having really bad cramping and lower back pain like af is coming into town. But she just left 6 days ago. Has anyone else expected this. And if so what was the issue???