Irregular Periods

Does anyone else have this problem? Before birth control I had my periods every 6 months. Got put in birth control after my first child. Haven't had a period in 3 1/2 years (implanon and nexplanon). And recently took it out in June 2014. Have been trying since to get pregnant with my second. On this app it doesn't have a over 90 day period track. So not sure when my next period is or when my next fertile day is:/