Skyla IUD and periods

So, I've had my Skyla IUD since January 26th, my period have gotten lighter with the same amount of pain. I was supposed to get my period 2-3 days ago and still haven't gotten it, only a little cramping. I know a lot of people stop getting periods on with IUDs but I thought it would happen sooner. I did take 2 pregnancy tests to make sure and they were both negative. Could it be my IUD or am I just a little late?