- Sherlock.- Molly looked at him. She was absolutely certain that something was wrong with him that day.- You're going home already? What's going on?
Sherlock turned to face Molly, wearing his coat.
- What? No, nothing's going on, absolutely nothing's going on- Said Sherlock with irony in his voice, which was turning into bitterness.- John is happy, Mary's happy... Everyone's happy.
Sherlock was just about to leave and come back on Baker Street, but Molly said something that stopped him.
- I... I know, Sherlock.- Molly said.- I know why you're acting like this.
Sherlock came to a standstill.
- It's... It's because of John, isn't it? You... You love him. Am I right?
Sherlock looked at Molly.
- Yes. You're right. But it doesn't matter now.- He said, sending Molly a weak, sad smile, after which he closed the door, leaving the wedding.
- Sherlock...

Mrs Hudson knew, how Sherlock was feeling at the wedding. She also saw Sherlock leaving. She was observing him through the giant window in the wedding hall.
She sighed heavily, looking down. She remembered her wedding, her friend that she'd never met again after the wedding, and she remembered that happy time which John and Sherlock had spent together before Sherlock faked his death to save John's life.
She remembered how desperate John was after that painful loss. She remembered when John announced he's getting married to Mary.
She thought that John and Sherlock had a thing for each other. And when it comes to Sherlock, she was probably right.
- Oh Sherlock, Sherlock...- She said quietly, wiping her tears with a tissue.
Mrs Hudson knew that nothing was going to be the same.

When Sherlock came back to his flat on Baker Street, the music from the wedding was still echoing in his head.

~Oh what a night, late December back in '63
What a very special time for me
As I remember what a night~

He looked around the dark room and decided to change his clothes into something more comfortable.

~Oh what a night,
You know I didn't even know her name
But I was never gonna be the same
What a lady, what a night~

Sherlock felt... Empty. He came back to the living room and curled up on a couch.

~Oh, I got a funny feeling when she walked in the room
And I, as I recall ended much too soon~

It will be better that way, he thought. John is finally happy, he has a wonderful wife and he's going to be a great father. It will be better that way.

~Oh what a night~

Suddenly, Sherlock's behaviour changed entirely and he immediately burst into tears, desperately trying not to sob too loud, almost choking on his own tears. He felt so vulnerable and miserable without John- he was like a little, scared child who got lost in the crowd.
He really tried to get that stupid song out of his head.

~Hypnotizing, mesmerizing me
She was everything I dreamed she'd be
Sweet surrender, what a night~

He recalled Mrs Hudson's story.
Nothing's going to be the same.
Now he will be alone again.

~Oh what a night~