I am 30. Before turning 21 I had my tubes cut tied and burned. I am a week late which has never happenned before. Is it possible that I am pregnant?

Possibly... Stranger things have happened. Take home a pregnancy test and call your gynecologist if your periods remain abnormal.
Unlikely. This is unlikely and maybe due to stress. A simple home pregnancy test can give you the answer if you don't start in the next few days.