IUD and period question!

Is it normal to miss a period on an IUD when you’ve been having regular periods?

I’ve had an IUD (Kyleena) since I had my son (it was inserted Jan. 2022). I didn’t have periods while I was breastfeeding for 2 years but have been having regular periods for the last year. Always starts at the end of the month and lasts 2-3 days. I missed my period in December. Is that normal? I know I should just test but honestly I’m nervous it might be positive. I haven’t had any symptoms though.