Never missed a period since my tubligation back in 2001. I am 7 days late. What is wrong? What should I do?

You could be stressed.
Your periods could be slowing down/stopping/skipping with age.
You could be hitting menopause, early or not (sort of same as age).
You could be lacking in iron or good nutrition in general.
You could just be late! Never say never.
You could be pregnant anyway. The chances are under 1%, but it does happen.
Something else!

What you do is nothing until your next period would be due (unless you feel symptoms of something else, or pregnancy). Mull over all the reasons above, and see how they might apply to you. You gave us no info. If pregnancy could apply, buy some HPTs in a week or two.