Lonelyness

How do I explain to someone that being lonely and feeling lonely are not the same thing. One can be lonely and not feel lonely. I get the loneliest when I am surround by a group of friends and I just don't know what it is happening, what are they talking about. It is like I am an outsider that doesn't belong. That's feeling lonely and not being lonely. I went to a small concert this week to see Making Marks, another norwegian band. I went completely alone as the person I call my best friend didn't bother to join me. Anyway, I was feeling ok, I don't mind going alone to a concert or being alone. I learned a long time ago not to fear being lonely. The only problem was that I was the first to arrive and one of the very few to watch the concert that was postponed in a few minutes to see if more people would come. I enjoyed my time reading the news on my smartphone. If I only had the courage and the words to go and talk to people, to the band. Anyway, I talked with no one, but at the same time I wasn't feeling lonely. I felt more pity on the band that didn't have much of an audience. Well, that's how I can explain this two different things.