IUD Question

Guinevere
Hey ladies, quick question.  This is my first month with an IUD and I'm extremely late for my period.  Now when I first got it, it basically extended my period by a week, so maybe it threw my off??? Anyway, I just wanted to know if this is normal. (Obviously I'm going into for a check up with my gyno soon, so I'll be asking her about it) but even so, I'm curious.