Did i make a mistake?

I had never really had attraction to girls, and now i have started being really attracted to some of the guys i have known for years. So a few days ago i just couldent keep it all in, and told one of my best friends (a girl) that i thought i was gay. She Was like "thats a new one" and proceeded to tell me that it was probably just a phase. So then i started asking myself if it was a phase. And came to the conclusion that I am. The a couple days later another friend was makeing a gay joke, something along the lines of "your not a f*g are you" to someone else, and i for some odd reason thought she was directing it twords me, and told her a bit later. She didnt seem suprised at all. While this has been going on, i guess my mom is sencing that something is wrong, and decided to ask me if i was having "girl trouble". That really got me sorta annoyed. I want to tell her, yet im afraid what she will do when i tell her. Im shure that she will accept me, but i dont know how long it will take. So yesterday, this girl was hitting on me. She had just gone through a breakup (where she treated the guy like crap). I just got over the edge, and annoyed, so told here I am gay. Now she is in some state of depression, and wont tell anyone why. Did I cause this depression? Is it my fault? Should i try to talk to her and comfort her? How should i do this?