A/N: My first fic, so please be kind. Trigger warning for self-harm.
Okay.
Three months.
Three months, four days, eighteen hours since he and John became more than just "friends" or "colleagues" or "flatmates", or whatever the hell it was that they were before. Not that Sherlock is counting or anything. Except he is. Because now he can hold John's hand, he can kiss and hug him at crime scenes, the Yard, or Angelo's (where they are most definitely on a date, thank you very much, so kindly put that candle in the centre of the table right this second), and it makes him so… so happy.
But now John is gone. Not gone in the sense of we-are-done-don't-ever-speak-to-me-again, but gone in the sense of I'm-off-to-a-medical-conference-for-the-weekend-don't-burn-down-the-flat-love. But gone is still gone and Sherlock is depressed in a way he hasn't been these three months, four days, eighteen and a half hours. He's dealt with it as best he knows how for as long as possible – immersing himself in cases, spending endless hours and Bart's, conducting horrid experiments in the flat – and he keeps telling himself that it's Sunday and John will be home in a few hours. But it's not working.
He's sitting in the loo now, on the edge of the bathtub, blade in hand. He hasn't done this in so long and he knows it will upset John, but then he remembers how this used to make his brain stop. And that's all he wants right now: he wants his brain to shut up, he wants to close the door to his mind palace and forget where he put the key, even if it's only for a few minutes. So he cuts. Right hand to left shoulder blade, extending the rows of small scars barely noticeable on his pale skin. And it feels so good. He knows what he's doing is wrong, that it's hurting John, but he can't think about that right now because there's another small sting when blade meets skin and then just relief.
And then the door downstairs slams and John's voice rings out through the flat and Sherlock freezes. He looks down at what he's just done and starts to shake, all sense of relief gone, because he realizes that what he's just done is more than just a bit not good. He hears John getting closer and starts to cry because he thinks he's finally done it. He's gone and ruined the one thing that's ever been good in his life for two minutes of relief.
The handle on the door turns and John is in the room but Sherlock doesn't stop crying because why should he? But John doesn't run away. No. Because if you can say nothing else about John Watson you can bet your life on the fact that he is loyal. Whether it's keeping the secret you told him in Kindergarten or holding your hand as you die on the battlefield, he will never break a promise he's made. So when he promises to love you forever, he most definitely means it.
So John doesn't leave, doesn't even speak. He just takes the blade and throws it in the bin and cleans the cuts, kissing the old scars to let Sherlock know that its' okay, it'll all be okay. And then he gets down on the floor with his back against the wall and holds all six feet one inches of his lanky, consulting detective boyfriend in his lap and just lets Sherlock cry everything he needs to cry while John holds him. And Sherlock knows that it's okay, that it'll all be okay, because John will always be there and will always listen. And that's okay.