I have nexplanon but my period is late

I need to replace my nexplanon next month, I got it put in on 5/13/16. But the issue I’m having is that my period is late by four days. I’m nervous I could be pregnant? But everything I read tells me it’s a good bc and that I should be fine. But I’m normally once a month for about 6/7 days have my period so it isn’t my normal pattern to miss a period. I’m hoping I’ll start and it’ll just be late but what do you guys think? I’ll obviously take a pregnancy test but I’m trying talk away what’s been going through my head. Thanks in advance ladies.