Why is my body public domain now?

How uncomfortable!! You mentioned this is at the work place..........I think your HR dept. needs to send out a memo on personal space. SERIOUSLY!!! It is all inappropriate.  

"My body is not up for discussion" is a fabulous response. Change the topic immediately, bonus points if it's for something obviously stupid (I'm a fan of "so how's that local sports team?"). If somebody touches you, physically take a step back, or pick up their hand and pu**** off from you-- bonus points if it makes a bit of a scene.

Shame is a fabulous motivator!