Do you change jobs often? I have to say that you're not perhaps dreading the new job but dreading appearing vulnerable. You say you present a cool exterior....maybe you should just accept the fact that a newcomer is vulnerable and don't fear people judging you.
Be a bit more "Who cares what people think!" I had to learn that...I cared SO much that people saw me as coole and calm and organised...well the fact is that I'm not and at almost 40 am unlikely to become so.
I just embrace my weak points...if people cant cope with the fact that I can be clumsy...tough! If they don't like the fact that sometimes like to be alone for a long time...tough!
Bugger them!Turn up, ask questions and do your best. That's all you can do! You can't please em all!