Trying to track my period with mirena

Hi everyone, I know some women get lucky and their period stops, but I got this app to track my period, and it's been really hard with the Mirena. I've had it almost a year, and sometimes I will have a period once a month, sometimes it has been one In three months, but for the past 3 months, it has been regular once a month. I am now two weeks late and wondering if others have a hard time tracking their period too?