This is called being ungrounded. It is not something you should just "laugh off." Basically meditating on your feet will help solve this. You should only be feeling other people's emotions WHEN YOU CHOOSE TO. In other words if you have no control over your empathy you are going to feel like you're be assaulted all the time.

Also one of the best books on the subject is called Empowered By Empathy by Rose Rosetree.