Zak: This is a tough situation, I don’t really know what to tell you. It sounds like you’re between a rock and a hard place. If you don’t feel comfortable coming out to your host family, I would advise you against doing so, since it’s probably best to stay on their good side. Are you in a larger city? Perhaps there’s a trans* community there (or at least a queer community) that you can get in touch with where you can go be yourself when you’re away from your host family.
Other than that, all I can really think of are little things, like wearing more androgynous clothing (perhaps male underwear or something like that), venting your feelings online, and trying to take your mind off of things. Sorry you’re in this rough situation, I hope you can find a way to make the best of it. If anyone else has any advice, please comment!