As for myself, I just pretty-much feel my particular loneliness, or perhaps it's more of an emptiness, all the time. I suppose the times when I feel it the most are when I'm not busy doing something. That's when the loneliness / emptiness bites the hardest.

It certainly is true one can not be alone and still be lonely. (Back when MSF was still Psych Central, there used to be an article in the archives on the subject.) However in my particular case, to a large extent, I have only myself to blame. As Leonard Cohen wrote in his song: "Bird on the Wire": "like a beast with his horn... I have torn everyone who reached out for me."