The first nightmare John as after the Fall is so bad that he awakes with a dry scream and barely dried tears clinging to his face. He wipes them away quickly. Lately he's been trying to save face in front of Mrs Hudson, and he's not letting up even at night. Externally, he's dealing with it much better than everyone else who knew Sherlock. He's heard from Lestrade that even people like Anderson and Sergeant Donovan, who liked to dislike him at the best of times, aren't holding up too well at work.
In his dream, he's rooted to the spot as he looks up towards the sky and sees Sherlock's still figure on the edge of the roof and suddenly he's running faster and harder than he's ever done before, his arms outstretched towards a falling body, Sherlock's, which is a hopeless whirl of black as it plunges to the concrete. Realisation settles in the pit of his stomach as he's sprinting past his endurance but the body's already on the floor, cold and dead and surrounded by strangers who gasp and ogle but in the end, they're not the ones who have to live with his absence. He's reaching out to touch him, as if his hands alone can somehow instil life into this man, the only man who John can say with absolute certainty, lived.
But now he only lives in John's dreams, the peaceful ones when they're at a restaurant table, laughing at the waiter's choice of socks, or sitting opposite each other in the flat, home, content with the silence of each other's company. Sherlock is – was – always content with silence, to tell the truth, unless it was filled with John's compliments or the melancholic notes of his own compositions.
His nightmares don't really stop for a long time. Maybe he's part of the reason for that. The only place in the world he can see and talk to Sherlock is inside his head, when he's dreaming or floating at the edge of consciousness, and even if it's a nightmare, he'll tolerate a thousand of them for one glimpse of him.
"You gave me a reason, Sherlock. Even my bloody therapist couldn't do it. But you did. And I actually had something to blog about because of the cases. Now there's nothing I could write on this blog that can compare with the times we had," John types silently, "so I'm archiving it forever. Well, until you come back, that is. Maybe we could start a new blog when that happens. We'd call it the Return of Sherlock Holmes." As John enters the last few words, his eyes briefly close.
He publishes the post, and halfway across the world a phone beeps. A pair of gloved hands tremble as the wearer sees the notification. He's sat inside a dumpster, shivering with cold, but the shivers he's getting now have little to do with the temperature. He clicks through to John's blog. He's silent for the few seconds it takes for him to read, and then tips his head back to rest on the metal.
He looks up towards the sky, which is half-obscured by apartments that tower overhead, and wonders if John can see the same cluster of stars he's seeing right now. He really needs to read up more on the solar system, but then again this is one matter he doesn't mind being ignorant on. He's been looking up a lot lately, to shake the jarring memory of the concrete rushing up towards him that he can't seem to delete from his head, to block out the constant feeling of falling. Out of a world of stable work and stabler happiness and into one that's moving around him all the time without lending him any time to adjust. Moriarty left behind an intricate web weaved around the entirety of the civilised world, and he's only just beginning to snip around the edges. He thinks back when his nemesis first started to lay the bricks of his downfall, and the outstanding memory he has is of John, the only person Sherlock has met whom he can describe as impassively defiant, and his remarkably unwavering loyalty to him, when all the facts pointed otherwise. Moriarty couldn't have left much to chance, but he didn't count on John.
Sherlock still gets erratic texts from Mycroft, the same stolid, bureaucratic master of wit he's always been. Mostly it's to update him on John's state of being, and Sherlock knows it's only a matter of time before he finds someone else, another flatmate or another girlfriend, and he also knows the two aren't necessarily mutually exclusive. It might take him a long time, but it will happen.
And when it does, John'll start by spending less time at Sherlock's gravestone, less time breaking the doctor-patient confidentiality code texting stories to him and more time with a new face and new memories, and the ageing ones of Sherlock will be pushed aside and shrink until they're an occasional nod to a picture that's coated in a layer of dust, or a light touch on Sherlock's armchair. He'll slip away, he'll move on, and Sherlock isn't quite ready for that, because if there's one thing he's sentimental about, it's John.
For now though, he's happy enough when Mycroft texts about his visits to the flat to periodically confirm the presence of the skull on the mantelpiece and the bag of thumbs in the fridge, because it means John's still holding on, holding a place for him; it means that one day Sherlock can still come back.