I grew up assuming I was straight. Why? I dunno. I've never been that visually attuned. Even to this day, I don't ogle hot guys unless I mentally decide I'm going to ogle hot guys. Attractive people simply don't "catch my eye" the way they seem to do for everybody else.
But see, even when it comes to THAT - the fact that I don't find people hot while going about my daily business - I never thought I was fucked in the head. I just came to the realization that I wasn't like everybody else, and I was cool with that. I never felt the need to pull out the self-flagellator and start punishing myself for it. Yeah, it meant I had to sort of feel my way through things my own way, but so what? I'm living my life, not somebody else's. Long ago, I decided I liked what I liked, and I wasn't going to let other people pick my fun for me. And that's true about the weird music I like, or the movies I watch, or who I want to fuck.
When I first realized I was gay, I didn't think anal sounded like such a good idea. I don't know if it sounded "nasty", necessarily, but it didn't appeal to me much. But once I got my first boyfriend, I suddenly decided I wanted to give it a go. I topped him first, and found out I really really liked it. Then, later on, I decided to go ahead and let him top me. And I found I liked that, too. Not as much, as it turned out, but I liked it.
Maybe it'll be the same for you. Maybe you need a living breathing human being to be in a relationship before you decide that you'd like to suck some dick. Or maybe you won't. But it would behoove you to keep in mind that most guys and gals like oral to some degree, and many (even straights) like anal, too. And I don't think it's because we're the ones that are fucked in the head.
Lex