Where the h*** is my period?

B

Why is my period a WEEK late? I have the ParaGard (copper) IUD. I got it put in oct of 2016. So I’ve had it for a little over a year now. And I track my period on her and it comes around like clock work. I checked my strings and they are in place so I’m trying to figure out what’s going on. If anyone has some advice please drop a comment. Thanks