Mirena first month question

I've been on the pill for 6 years and just switched to the Mirena (Jan 4th) because I started to forget to take my bc. I haven't had to keep track of my period in so long because I could just look at my pill pack, and now this app is saying that I'm a few days late...is it possible that it's just the IUD messing with my hormones? Has anyone's period stopped or gotten lighter in the first month of having it?