It's too much, all too much. It's a noose around his neck, a constricting in his chest. He's empty and overflowing all at once, running on the last of his reserves. He could die at any moment. Just collapse and give it all up. (Would they care? Or even notice?)
Moving is an effort, yet he must. It drives the thoughts from his head, forces him to work around them. How he wants to just lie in bed and stare at the ceiling, not think, not feel, hardly even breathe. To hell with the cases. To hell with John. To hell with it all.
Just give him some peace.
Yet, he can't do it. He needs the cases, they force him to focus though the effort is overwhelming. And John. He craves John like the drugs he once allowed to flow through his bloodstream. It hurts almost as much, withdrawal from John. John's own decision – he has his own demands between work and Mary. It's selfish and wrong to ask him to sacrifice something to fit in him, Sherlock.
He's already hurt him so much, between one thing, and another.
Mycroft doesn't understand it. It's beyond him to feel like this, but he does his best. And though they have their differences, Sherlock has never felt so grateful for his brother.