New to the app...

Husband recently decided he'd be up for trying to conceive, we've tried twice but I have no idea if I was fertile. I downloaded two apps to check my fertility and plugged in my periods from the past year but since they are very irregular the apps are not really able to calculate since I haven't been doing temperature tracking.

It hasn't been very long, we started trying the 14th of feb. but the last three days I've been crying over nothing, my breasts hurt and today I'm exhausted. Since I can't rely on periods to know when I'm late or have missed one, does anyone have an idea of the earliest I can take a test?