As an add-on to my original post:
I should probably add that when I was younger and I'd play dolls with my sister, I always preferred to play the male ones, and even now when I roleplay online and write stories, I prefer to play male characters and write from a male point of view. I'm also much more comfortable saying I'm male on forums/websites/etc, when I'm actually not, and occasionally I actually get my sister to tell people I'm her brother. A lot of people on other websites think I'm male when they talk to me, as well, without even knowing my gender initially.

I feel so confused. I really wish I could be a guy, and I'd feel so much more comfortable with myself if I was, but everyone I know wouldn't accept it.