Hi Dan,
I used to be lonely at a football game with 80,000 people around me. The thing is that I also hated to be by myself so I would hang out with people all the time to not feel so lonely. After lots of exploring I found that my lonelyness and my hating to be by myself was due to the fact that when I was alone I was with me and I didn't really like me and when I was around people I didn't think I had anything good to share. The key for me was to discover the fact that I am a good person and have alot to share. I began to learn how to love myself. One of the things that I do every morning is when I look into mirror I greet myself with a big smile and tell myself to have a great day, after all I do see myself every day so I want to be sure I start my day in a positive way. I know it sounds weird but it works. If you do this be really happy to see yourself the more you express yourself the better it works.
Open your heart and look inside many of the answers you seek are there. The more you love yourself the more you can love others.