Wildcat,
Deep Breath!!!!!!!!
I completely relate to what you are saying (albeit my office is small) but the others take advantage and whisper and make plans and then pretend that nothing happened, or they will say things just loud enough for me to hear and let me know that I am not included. Women are B#$*$#@.
If it is an issue that is really bothersome, bring it up with your boss. The boss usually has some training on how to deal with the unruly teenage girls that are giggling in the back of the room making everyone else uncomfortable because of their own lack of self-esteem.
You are not childish and your thoughts and feelings matter. I don't find you difficult, I find that you induce me to think more in the gray areas, not just the black and white. I will say it again, it is easy to point out the differences in others than it is to recognize it in ourselves, you are thinking black and white, look at the gray.
Now as for your test in May, you are not to miss that for anyone, anything or blah, blah, blah. This is a must and if you need to talk to the Boss, talk to the Boss. This woman cannot demand you put your health in jeopardy because of her selfish desire to have a holiday (holidays are important, but not as important as your health). Besides you asked first and were granted the time off.
I had an ultrasound done on my heart and the tech (very nice lady) was very gentle with my breast, she had to wiggle this way and that way and push here and there but all in all it was ok. I believe most tech's are nice and only the mean ones go into mammograghy not ultrasounds :). So again deep breath.
Remember, we are here for you whenever you need a shoulder or in this case a computer to lean on.
. Ah well, i brought my daughter's left over breakfast as my lunch-time desert (white flour raisin bread with marmalade) to have with an extra coffeeee!!! It helps to pass the mechant.
The new girl has new friends now that the iron glove is not terrorizing some of the others. 
