I feel exactly the same and it happens whenever I'm in tune with what seems to be -true love-, the love you see in helping one who needs help, working for a better world, seeing happiness all around, being "part of the whole", someone devoting their time to writing such a beautiful piece of music and all alike.
I think that when we focus on those experiences, we tune ourselves to some sort of hightened frequency, making it easier for us to feel or to absorb energy around us.
I've heard a spiritualism expert in my country report a experience that reinforces this concept of "universal love" being linked to energy that I have exposed. (he gives out a bunch of lessons on all we talk about here, but they're all in Portuguese-Brazil

If anyone wants to look for some of his work, his name is "Wagner Borges" ). It goes this way:
During a group meditation practice, while he was setting up his students for their work, he noticed a man laying on the floor by his side. The man was dead, looked terribly pale, consumed and putrid. He had worms and other insects all around him, can you picture such a sight? Imagine this man's suffering, being dead for who knows how long and stuck to his physical all the time.
As he noticed the man, he couldn't help from feeling gross, but he managed to send him some energy form his heart chacra, in an attempt to help him. After some tries with no success, he noticed another being entering the room. This time, it was a beautiful woman with long black hair who simply SHINED LOVE. He felt a extreme surge of love and energy and received a message from her. She said that, when trying to help others, it is important to send out not only energy, but also love, since energy always follows love. Having said that, she took the man in her arms as if she were holding a child and went upwards, fading away. After his experience, he stopped his class and told his students about the amazing situation that had taken place just a few feet away from them.
Do you see what I'm talking about? It's being in tune with this feeling that makes us vibrate that way, the feeling universal love gives us.
Hope to have helped a little

Horacio.