Advice/help please!!

I have an irregular cycle (also a little overweight, trying to lose it! :( ) I have two fertility apps on my phone that I use daily & enter the same data. Only this month has my other app had different results in it. It had different days for my ovulation & different days for AF. Other says AF is 3 days past due but glow says I'm not due for AF until the 31st. When should I test?!?! I'm having slight symptoms. Advice? Help please!!