Probably not, but if you rreally concerned you should see a doctor. I know thats probbly not an option at this point seeing as your parents dont know your concerns but it really would help a lot.
There is a chance, that your just causing yourself to feel this way because you think your pregnant. It happens to a lot of people, you will actually begin to experience symptoms and whatnot even though you arent pregnant. Just because you think you are. Are you stressed over this? If you are, try calming down and see if that helps. Theres a possibility that your late because your stressed.