The hitman is right. Just in case, you can always get one more test, if they both come back negative, then I would double his bet. Your period is not as good of an indicator of your pregnancy as a test. Then in about two to three weeks, if you have not had your period, you can test once more. If it comes back negative, then you really shouldn't be pregnant.
If the tests come back negative, but you are still experiencing different symptoms, then you can see your regular doctor or gynecologist.
I am assuming your test came back neg. If I were betting, I would say you are not pregnant.