Pregnant with tubes cut and burnt

Deannamack
Hello I'm Deanna I am now 5 weeks and 5 days into my pregnancy which I'm very surprised due to the fact that I had my tubes tied cut and burned back in July 28 2016. So yes 4 months after having my tubes cut and burned I am now 5 weeks and 5 days how can this be. I would like to know has this happened to anyone else. I am also wondering how does this happen