There's an appropriate time for excessive, over-the-top behavior, but today is definitely not it! Try on a more demure demeanor and see how it fits -- it might be a lot more comfortable than you think! You need to fade into the background, get back in tune with others, and find out what they want to do today. Being more passive with your coworkers shouldn't make you nervous. It's not a sign of weakness, it's a sign that you know how to be a good team player.