You have a lot on your plate right now, and in times of stress anxiety can definitely peak in my opinion. Not only do you have a new child, but you are starting a new job....that can add a little stress to say the least.
Have you had anxiety issues in the past? Is your new boss a good person and you are just nervous because you are new in the job? I think being anxious in the beginning of any new experience is quite normal in my experience....keep us posted!
Sometimes...no all the time when I get out of my routine, I freak and it takes me a while to get back to work if I have been on vacation!!! Nothing is wrong with you...why the heck is the boss standing there listening??...unless it is about some great idea you have!!! The next time you see him come over start talking about ome subject he can't stand!!! Sorry just trying to add some humor...I quit my job of 20 years because I could NOT work with the new people...good luck!!!