Anyone else have irregular periods?

I got off birth control (Nexplanon arm implant) on January 25, 2017 after only 6 months. It made my periods super irregular and these couple of months I never know when to expect it. It makes it hard to track when I'm ovulating too. I can never rely on any apps to predict when exactly it'll start because it honestly just has a mind of its own. Me and my SO have been trying to conceive for 3 months now and every month after my period arrives it's super disappointing. I just need to know if any of you have irregular periods and how you go about monitoring OD/fertile days?