Alone or Lonely? Have you got to be alone to feel lonely?

If I say I'm alone, I mean that there isn't anyone else with me.

She's alone in the house tonight as the rest of her family has gone out.

I like to be alone sometimes.

Sometimes, we use 'on my own' instead.

You shouldn't go out on your own at this time of night.

These following sentences are all correct:

Sheila prefers running on her own.

Sheila prefers running alone.

Sheila prefers running by herself.

If I say I'm lonely, however, I feel unhappy because I'm alone, or because I have no friends.

Wikipedia: One way of thinking about loneliness is as a discrepancy between one's desired and achieved levels of social interaction.

So, you could be in a room full of people, but yet feel lonely because no one is talking to you.

Sarah feels very lonely after her husband left her.

Lonesome is a synonym for lonely, although it's more common in US English.

Remember Elvis? Are you lonesome tonight? Do you miss me tonight?

Listen to this tremendously moving song by Ben Harper.