Hello, I would be happy to help you with your question.
It is unlikely that you are pregnant if you have a negative test in the setting of a delayed period. It is not uncommon for there to be some variation in terms of when you ovulate as your body clears the hormones from birth control pills. I would use protection (unless you are trying to get pregnant) and repeat the pregnancy
test in one week.
I hope that this helps. Good luck!