Not ovulating

Stephanie • Mother to a sweet baby girl born 14 October 2015 💗👑💗
I went off implanon I'm July of this year. Since then, my cycles have been irregular, but I've been using OPK's & temping and know that I definitely ovulated in September & October. I'm on cycle day 24 today and have had nothing but EXTREMELY negative OPK tests, and my chart also confirms no ovulation. I'm so bummed & frustrated. Don't know what's happening. :(