I was never less alone than when by myself.

Solitude and loneliness are not the same condition. Alone, the company you keep is your own thinking, and it can be better than a room of people who all need something from you. Loneliness comes not from the absence of others but from the absence of anyone you can be yourself in front of, and a crowd produces that as easily as an empty house.

Notice which of your empty hours restore you and which leave you hollow. If time by yourself has become something you dread, give it a shape, a walk or a book or a long task, rather than waiting to see how it feels.