Period 4 days late!

Kayla • Kai 🧒🏾💙 11/29/18, Baby Boy 2👶🏾💙 3/11/22
Okay so my period is four days late. My cycle had been working my clock work since October 27 days, 28 days, 27 days, 28 days and so on. This cycle would be 28 if following the pattern but nothing and no positives. What do you guys do in this situation? O day was 31st and my period was suppose to come on the 12th.