Hi Amber,
I'm near Indianapolis and there are a few groups in Indy that meet once a month if you're willing to make the trek. Two of them meet on the same day of the month at staggered times to allow people who travel a long distance to attend both as I understand it.
As far as any laws protecting us, Indiana is pretty far behind the times from a legislative standpoint. To my knowledge gender identity isn't protected here.

You should check to see if your company has some sort of diversity statement, most do nowadays. Gender identity is becoming pretty standard in a lot of them.
I know how you feel, I work in manufacturing in a *very* male dominated environment. Trust me, I've heard it all. It's definitely a factory environment. When I approached HR about coming out at work they were incredibly supportive and we're working through the details now. I'm planning on making my announcement publicly on Nov. 5th and will begin coming to work full time shortly after. So there
is hope!
If you'd like any contact info for the groups here let me know and I can PM them to you. I'm not super familiar with one of them but I can find their info pretty easily.
Good luck, and hang in there. You're definitely not alone!