Should I be worried?

So I keep saying I'm not worried because I'm really not but I just need a another opinion. I have the Mirena IUD, we use a condom and pull out. My Mirena has only been in for 4 months so my periods are supposed to be a little crazy for a bit. My last period ended like January 8-9ish somewhere around there. The eve app says my period is to start this week and it hasn't, but it doesn't take into consideration I have the IUD and my periods are 2 weeks long with the IUD so really my period should be next week. Also I've been very stressed lately at school, know stress will cause changes in ur periods. I would really appreciate another opinion. ❤