Some of my personal experiences (way to many to do in one post!):

I did not know I was an "Empath" until I met another who affected me so strongly, and at the "end" we realized what had been happening all along.  See, positive empaths, well, they tend to bring out the best in us... but a negative empath, well, that can be disastrous.  I could not figure out why I felt down, depressed, upset, unsettled all of the time.  Then once I knew it was over, we were discussing how I had said he was unhappy here and he was arguing that he was not (our common argument).  Until I said, I can feel you, I feed off of others feelings, did he/we understand what had been going on the entire time.  Also explains why we ended up together so dang quick.... we even had the same birthday.  BUT, once he moved here, away from his kids, mom, family, friends, he lost a part of himself, and was staying for the wrong reasons.  That is what I felt the entire time and didn't know it.  I could start crying for no reason, and someone knew nothing was wrong with me... It took me a long time to learn the difference between my true feelings and me feeling someone else's feelings, and how to gain control of that, once I identify it.  In short, we were mirroring each other, except he was a negative, and it took me over completely.  Truth's come to me in the shower, something about the water... and I was in the shower, tears streaming down my face, for what reason, I didn't know, just knew he had to go.  This was actually at a time that I needed him most, but I knew he had to go then.  He walked through the door to tell me he had a call for a job, and I told him no, sit down, pack your backs and you are leaving tonight.  Stunned was the least of it, but we both knew. 

It was after that, that I learned to start paying attention more.  More to my feelings, those around me, and started realizing "wow" how f*&^%$ up this made me... and how I had no idea how to deal with it.  I would be at work and all of the sudden feel sadness so badly that I could not work majority of the day.  This happy-go-lucky girl all of a sudden took on another persona... and others must have noticed, because I would get questioned as to if I was OK or not... and I would say no, but I don't know what is wrong with me.  Later I found out the girl across from me was internally hiding how upset she was over her husbands abusiveness and she was having to get out for the safety of herself and the kids.... another day I came home to find my guy sitting on the couch, totally distraught, because he was worried all day that I was going to break up with him.  I had felt him from work all day!  Another time, a year or two earlier, my son, who is military, was stationed 10 hours away and had just gotten back from one of his tours over in Iraq, and tried to surprise me... problem is, all week I had the feeling he was coming to town, and a couple of seconds before he arrived, I was standing at my linen closet folding towels and I said "he's here".... then came a crazy pounding knock on the door right after... "surprise!!!!!".  How do you surprise someone like me? lol