 Lonely, I am so lonely, I have nobody. Okay, sorry for that out-of-tune singing, but we were just trying to get your attention. Feeling lonely? Then you're not alone. A recent Gallup survey shows one in five people worldwide say they feel lonely a lot, which is very damaging to us as humans. We're a social species. We're at our best when we're with other people. ABC News medical contributor Dr. Alok Patel speaks with ABC's Diane Macedo.