My periods are irregular and i use 3 different trackers. "My calendar" I've had since july 2013. Then glow and ovia I've had since April 2015. Got the last 2 after me and the hubbys miscarriage. I am more apt to believe the my calendar since I've had it longer but its hard to know when i am ovulation since the others tell me something different. Just wondering others opinions on this I've gone back abd counted days coming to the conclusion my period is anywhere from 21-28days. I have tried bbt, opk and cervix position but so far it is never on target and i have never gotten the opk to work. So honestly now we are having sex every other day. Its fun but tiring since we work different shifts. Just anyone else had this problem?