Oh, it's not that bad

I was in the same situation.... I work for Lowe's... My HR manager informed the whole management staff at the weekly meeting that I was Trans and that I would be starting transition at work; They were instructed to go and inform each of their employees. Well this was done on the first of two days off for me so by the time I arrived at work two days later, I had (by proxy) come out to about 130 coworkers.

Woohoo!
Funny thing is, no one said anything on the first day... I noticed that some were a little strange with me but not a word was said. On the second day, an employee I rarely talked to walked right up to me and said, "I admire your courage." She gave me a hug and went on her way... I had very similar reactions over the next couple of days, from men and women. What I found is that most people, although they've heard of "sex change operations," were absolutely clueless about transsexuals and were very curious about me. I was very candid about why I was doing what I was doing, what they could expect to see and how, if at all, my transition would effect them. I also have a hefty sense of humor about myself... that seemed to disarm the skeptical ones more than anything else. I armed myself with information and wasn't afraid to educate anyone who would listen. I've continued being quite open about the whole process... One guy, much younger than me, stated that he felt privileged to be able to watch the process... "This is something that so few people get to see," he said. Another, older, woman said that I changed "seamlessly from man to a beautiful woman," right in front of her. I started out hoping that I could show all those people that a Transsexual could be pretty cool to work with and, for the most part, I succeeded. They're very excited about my upcoming surgery. I know this may sound like an unusual story... I feel very fortunate to have such a large group of supporters but I feel that my attitude had 100% to do with how they reacted to me.
I did have one very obvious negative reaction...... About a week after I came out, a ..... I'll be nice... "very religious man" approached me and grilled me with questions.... He started asking about the relationship I had with my father, if I had been abused, if my parents used drugs.... I actually answered his questions and diffused the notion that being Trans had anything to do with my upbringing.... Later in the day he announced that he wouldn't be able to use my new name or refer to me as "she" or "her"... he said it wouldn't be right. I said, "fine," and marched to the HR office. They shut him down!!! His issues resurfaced when, a few weeks later, he still wouldn't use my name... so I threatened to start calling him "Buttercup," in front of as many people as I could... He thought for a minute and said, "Ok, Jess." He still isn't happy but we tolerate each other. There were a few women who's jaws hit the floor when I showed up in the ladies' room but the shock wore off quickly.
Over all, I think that the most important thing I found was to not put myself in their business... I think that some were expecting lots more drama than I ever generated. I would say, "I'm not asking you to condone what I'm doing, just accept that I'm doing it." Lucky for me, too, that Rhode Island has gender identity written into anti-discrimination laws.
Anyway, good luck tomorrow and really..... We work ourselves up to more than it really turns out to be