pregnant or side effect?

so i got my nexplanon inserted on May 1st, 2019 and once the week passed to where it was effective my boyfriend and i stopped using other contraceptive methods (condoms, pulling out, etc). my periods are always very VERY regular, but i am currently 6 days late. i want to brush it of as a side effect since the nexplanon is 99% effective but what do you guys think? do yall know of anyone getting pregnant while on nexplanon? did your period get irregular or disappear on nexplanon?