It's never "comfortable" to "out" ones self...but it won't kill you either. (unless you're in the wrong country or talking to the wrong people)
I wasn't implying that we should go running around screaming "I'm Trans"...I just think you need more confidence girl. If we go around living our lives in fear, how can we open up to love and care about others? Living with constant fear is surviving, not living.
If you want to be out, be out; if you don't want to be out, don't say anything. Just don't live in fear of other people thinking differently of you, after all, everyone has negative thoughts about other people; and none of us can change what other people think of us (not US as transgender), everyone has the right to think what they want after all.
If you can't change it, why worry about it?
Besides if the assistants out you after you've given them your preferred/changed name, you can go to the people higher in the system and complain. There are always options and choices.
It's up to you if you want to tell the doctor that you are trans, it just makes the doctor's job easier if you are honest with them. Without all of the facts a doctor can't diagnose a health problem correctly, which could in turn harm you because you didn't get the proper care.
It comes down to...
Being outed Vs. Being treated incorrectly and possibly dying