You would be amazed at how many of your friends may end up saying "I knew it was something like that" when you finally do tell them. I know for me personally, I was actually surprised at how many people in my life took the news like it was nothing at all, kind of like, "ok, tell me something I didn't already know."
They could also just think it's some sort of cross-dressing or drag thing too. Others might also not say anything because they just don't honestly know what to say, and don't want to offend you.
Since you are seeing a therapist, maybe you should just come out?
I did that myself on FB. I had a "male" page before my "girl" page and wrote a long note on my boy page about being trans and requested that everyone read it then add my "new" page to stay in touch. Once everyone was on board, I deleted the boy page and that was it. I've been April ever since. Of course when it came to family not on facebook I just told them, but amazingly, nearly all of them have been completely ok with it.
Hey, would you want to friend me on FB? That would be awesome =]
~April