This is the first time iv ever really tracked my menstrual cycle and ovulation. I just got my iud out after it was placed 10 years ago after the birth of my son. Last month my cycle was 40 days, according to this app i should be at the beginning of my ovulation, iv used the riteaid brand ovulation test 3 days in a row which is supposed to detect 24 to 48 hours in advance. But nothing. No line in the test not even a faint one and the control is a nice bright red. My peak ovulation is supposed to be monday the 3rd according to the app. Should i keep testing? Is it possible that my cycle is off bc of the iud?