Frustrated and confused

So, as if having irregular cycles, and being told I'm probably not ovulating wasn't hard enough, the two apps I'm using having my at very different points in my cycle! I bbt and opk everyday, and enter in all the same information. Still haven't had a positive opk yet, but according to Fertility Friend, I'm 4 dpo (based on bbt and cm), and according to Glow, I still haven't ovulated. That's a big difference, and I just don't know what to think....