All by Myself by Eric Carmen (Céline Dion version) is featured in A Night of Neglect, the seventeenth episode of Season Two. It is sung by Sunshine.
Sunshine states that she wants to help the New Directions with their benefit concert because she says that she understands what it's like to be in a decathlon group; no one pays any attention to you. She says that she has hundreds of Twitter followers, who she can get to come to the benefit to help raise money for the New Directions' trip to Nationals.
The song was originally recorded by Eric Carmen from his first eponymous titled album. It was reinterpreted by Celine Dion for her fourth English language album Falling Into You, and her version is the one sung in the episode.
Sunshine:
When I was young,
I never needed anyone.
And makin' love was just for fun.
Those days are gone.
Livin' alone,
I think of all the friends I've known,
But when I dial the telephone,
Nobody's home.
All by myself,
Don't wanna be all by myself anymore.
Hard to be sure;
Sometimes, I feel so insecure,
And love so distant and obscure
Remains the cure.
All by myself,
Don't wanna be all by myself anymore.
All by myself,
Don't wanna live all by myself anymore.
All by myself,
Don't wanna be all by myself,
Anymore.
All by myself,
Don't wanna live.
Whoa.
Oh.
Don't wanna live by myself,
By myself,
Anymore.
By myself,
Anymore.
Whoa.
Trivia
This is Sunshine's second solo on Glee and her second solo in the auditorium, in front of New Directions. Her first solo was in the first episode of Season 2, Audition, when she performs the Dreamgirls classic, Listen.