I'm an empath too and haven't really attempted to learn how to shield myself from negative energy (I know I should) and some people are good at that. It takes practice.

I think that dark spirits can and do gravitate to light ones because of their energy. Happened to me all the time. Its part of the reason why I left my job. There were other factors, but I just couldn't handle it anymore. Sometimes if you find yourself in a relationship or friendship with someone like that, then there is most likely a lesson to learn there but they also feed off your energy even if they don't even realize it. I think that is why there were certain people in my life--sometimes directly, and sometimes indirectly that caused some serious depression. They really can bring you down to their level.