I had a tibal 13 years ago and my period has always been regular till this month now i am 18 days late and feel pregnat could i be?

You need a preg test: Tubal ligation is a method of birth control and like all methods it can fail. While there are many other explanations for your late period, pregnancy must be considered. Up to 1/2 of pregnancies after a tubal are ectopic (outside the uterus or stuck in the tube). This can be a life threatening emergency. Do a preg test and if it is positive see a doctor or go to the er immediately!