My fiancé and I have been ttc for 5 months, this cycle we have just started using ovulation test strips. If they are correct, the tests show I was ovulating on CD13. As expected after this the lines on the tests then got fainter and fainter. However I took another ovulation test on CD21 and CD22 and the line is getting a lot darker again! What does this mean? I have some cramping, lower back ache and nausea. Could I be ovulating again or could I be pregnant?!