What is going on

My periods are always regular, always!!! The only time my period was ever late was when I was pregnant, it was 3 days late I tested and it was a vvfp okay and I had my daughter 10 months ago and up until now my periods are regular but this month so far it is 9 days late! I tested when I was 6 days late and it was definitely a negative I think??? Did I test too early by chance? Has anyone not got a bfp at like 9 days late but was still pregnant I will most likely go to the doctor soon if my period doesn’t come