Help!

So I am trying to conceive however I cannot track my ovulation days because my period has been jacked up since I had used a BC pill a year ago. Now my periods can disappear for months at a time so I never know if I'm pregnant or just waiting on my period.
​Can anyone suggest what to do.
​all I remember is my last period was in late July or early August.
​The app I used to track my period on got deleted :/