If you like, there's a forum dedicated primarily to transgender and transsexual people, but they have a lot to offer for anyone questioning their sexuality and gender. Just Google "Susan's Place", it will be the first hit. The people there are incredibly welcoming and friendly and offer loads of information on the subject of gender. (Sound familiar? )

The thing about people not believing you - well, it's understandable, albeit frustrating for you. I'm sure some people don't even know hermaphroditism/intersex is a real condition. It's simply because they aren't confronted with the condition until you tell them. And if you pass easily as a female-bodied person, they're even less likely to believe you. Many people probably have very crude images in their head of what a hermaprodite looks like.

As far as sexuality goes . . . sexuality is determined by the gender you identify as. If a person identifies as male and is attracted to other male-identifying people, he probably identifies as gay. Even if that man is biologically female or intersex.

If a person, identifies as neither or both male and female, determining one's sexuality can be complicated. I myself prefer to be gender-non-specific (I'm biologically female but I make a very manly woman and a very feminine man, so I've simply cast aside society's binary gender system and just started being me). I used to identify as lesbian as I'm mainly attracted to women but now, I just leave it simply as "I prefer women" as opposed to "I am gay/straight".

I hope this helps and if not, well, I pitched my two cents