Hey Sunshinebird,
I'm a trans guy who's not straight. I prefer to just not label my sexuality because I just feel like it's largely irrelevant, the sexuality of a person shouldn't matter unless you're sleeping with them, right? I'm not a stranger to feeling like I'm not trans-enough because of my sexuality, though, although as Cindy said, gender and sexuality are completely unrelated, so (for me) it comes down to the dysphoria of possibly not passing because of it.
I can assure you, however, there are loads of other gay and bi trans guys, as well as every other sexuality under the sun. An Australian research sumary from BeyondBlue on the mental health and well-being of gender diverse and transgender young people in Australia actually shows that 50% of the participants identified as queer and or pansexual compared to only 5% as identifying as heterosexual. Of course, these are just Australia's statistics, but unless we've got something funky fresh in the water, I would say it's a safe assumption that the rest of the world might have a similar outcome.
I'm always happy to help out.