I'm not gay, and I hate that my mom lumps me in with being a lesbian. I mean she's coming around, but she still thinks of me as a lesbian. It pisses me off so badly I can't even handle speaking with her.

I know I have to keep in mind that she is from a small town in TN and has no formal education, so I know she's just really ignorant to the situation, but it is suffocating me.

I really don't know what to do. I have said four or five times that I'm not gay. I'm a straight male. To which she replies that she doesn't "get it"

What should I do? Just not talk to her?

I'd never say "don't talk to her" I'm a total mummy's boy :p however, perhaps you could watch a documentary or something with her? Educate her on it a bit, though that could only work if she is willing.

May the force be with you!

yeah try edducate her thought documentarys/groups/articles or anything you find interesting, on gender sex and sexualety.

if she dont get it then its probably because she is very stuckt in the hetronormative world and dont have much knowlegde about anything outside.
she might know about being a boy or a girl or being straight or gay, but gender and sexualety is way more fluent than this, and thats what I see the point she dont get. (sure I dont know your mother so I could be wrong)

you should try show her the documentary I think its called sex lies and gender?? or something like that, its very interesting and show a vide view of all kinds of transgender,
or you could also find a documentary about only transexuals who are straight or interviuws, I wouldnt recomend a movie, since I fell the only good ftm transmovie are gay and it would be stupid to confusse her even more.