Does anyone have advice on Telempathy?

For several years now, I have been able to perceive and discern many people's emotions. While this is usually limited to people in my direct vicinity, I often experience massive overloads of negative emotions, with no apparent source; and they certainly aren't my own. I once dated someone who lived over 2,000 miles away from me, and I would experience an extremely powerful feeling of panic and despair from time to time. I would find out later that the feeling was right around a time when she was angry or upset with me. This occurred many times, and I eventually broke up with her out of frustration with her continual anger toward me. Back to the point: I want to develop my telempathic ability, as well as learn to control the negative side of it so that it does not overwhelm me. Any advice on the topic is appreciated. Skepticism and discouragement is not, and will be reported.