OPK, you win! I give up!

I have started using OPKs this month and quite frankly I've had enough already! They make no sense whatsoever! I started testing the day after my period and got what looked like a positive or near positive 4 days later, not in my fertile period. Continued to test with all results being negative right up to the last day of my fertile period... What?!?! Did I ovulate early? Or not at all?! I'm regular as clockwork usually. It's so confusing! Not going to bother next month... Anyone else had this problem?? X