Periods after tubal ligation

Dana

Okay I had my last baby in August of 2017 and got my tubes tied afterwards. My period came back in September and from then to December it was spot on the with my app but January it was 4 days late and this month it was 5 days. has anyone else experienced this? it freaks me out ive never missed periods or been more than a day lately except for when i was pregnant.