Took a pregnancy test a day after i took plan b, it said negative, is it true or is it my hormones since my next cycle isn't until 09/15...

Took test too soon: Hi. You probably took Plan B at the appropriate time, so that would make it too soon to have taken the pregnancy test. If you MISS your next expected period, take the preg test about a week after missing the period. But don't worry in the meantime...Plan B is highly effective. Good luck, and use effective birth control regularly to prevent undesired pregnancy.