feedback please 💙

I have had my iud mirena for almost three years now and never really had an issue... my partner and i have unprotected sex and i am a week late on my period is this something that can happen with this bc? I cant afford a baby atm... i have no period symptoms at all so im low key worried but not to the point where im stressing on it bc i know that can be bad too..i was looking back at my tracker and noticed that there is was a time where i didnt have a cycle within 52 days 🤔