We don't know if you're bi or not, either. That is something that you have to come to on your own.
There are a lot of resources on the main site that can help you figure out what you're feeling, though. Browse through these articles for more:
The Bees and...the Bees - A Homosexuality and Bisexuality Primer
Bi the Dozen - A Bisexuality Quiz
We have a whole area of the boards devoted to Orientation and Identity as well. See the FAQ for that forum here:
Orientation & Identity
"And when the answer that you want/Is in the question that you state/Come what may..." - Coheed and Cambria, "Blood Red Summer"