Nexplanon. HELP

So I’ve been on the nexplanon implant since March 2018. Before this, my periods were regular, but now they are really heavy and more frequent than usual... some months I will be on for a week, have a few days off and then back on for another week...

But I have noticed that I haven’t been on for longer than a month now, I’m worried about being pregnant but I know the effectiveness of the implant is very high so I am confused. If I’m still not on by Sunday then I will take a test,

But I’m just curious to see what everyone thinks and if anyone actually knows of any situations where someone has fallen pregnant on the implant.

Thank you in advance!