Delayed Reaction by 
thirty2flavors
Delayed Reaction
Notes: In response to a prompt for the lj community nest_of_spiders. The prompt was a line of Dumbledore's from Goblet of Fire -- "Numbing the pain for a while will make it worse when you finally feel it."
--
Sirius does not let himself feel the grief - grief over losing them, grief over losing everything
-- until he sees Harry.
He doesn't let himself feel it when he goes to Peter's flat only to find Peter missing. There are still plenty of other explanations, however unlikely, and his mind remains optimistic as a mere matter of self-preservation. He cannot let himself believe the worst before it has been confirmed, and there is double-checking to be done before he jumps to the wrong conclusion.
He doesn't let himself feel it when he arrives at Godric's Hollow and sees the wreckage of the cottage. He finds James' body first, and grief begins to work its way to the outermost edges of his consciousness, but he shoves it away valiantly. Any emotion is better than the unbearable impending heartbreak, and so he throws himself into anger and hatred instead.
It is Peter's fault, and Peter will pay; for three days that is all Sirius will allow himself to think about. The rage is all-consuming, and it works well to dim the memories of the pale, lifeless things he found in the Potters' foyer, in Harry's nursery.
When he faces Peter again, it is easy not to feel it. The anger seems to have transfigured into madness and he is not even aware it's a defense mechanism anymore. It feels like killing Peter will fix everything. He worries temporarily that James will be angry Sirius has not waited for him, that James will have wanted to do it himself. Sirius decides he does not care - James is never angry with him for very long, anyway.
When the smoke clears and Peter has gone and Hit Wizards are surrounding him on all sides, the sheer lunacy of the entire situation occurs to him and he laughs for the last time in twelve years.
In Azkaban, he has no choice. The first Dementor brings back Halloween almost instantly, and without Harry's wails and the blubbering, bumbling explanations of a half-giant, there is no distraction to hide in. He struggles to stave off the memory but the Dementors are stronger and Lily and James' lifeless eyes seem to follow him at every turn.
But there are other memories - dozens - that stumble over each other in their attempts to make it to the forefront of his thoughts. The funerals of several Order members - fight after fight with his family - running away - Remus in the Hospital Wing, viciously battered after nearly murdering Snape - Regulus disappearing, presumed dead - James' heartwrenching, unashamed sobs at his mother's funeral - there are too many memories for him to focus on one, and in the din and confusion, he thinks that might be a blessing, really.
After twelve years he is used to it. After twelve years, he is used to everything.
So it surprises him when he spots Harry in Little Whinging and - even as a dog - something prickles uncomfortably inside him. He finds a good spot to hide that night - somewhere safe, somewhere he can be himself and think the clear thoughts of a human rather than the muddled thoughts of a dog.
It's as he sits there, thinking of Harry's face (so very much like his father's), that the last twelve years begin to sink in. The tightness in his throat feels foreign and ancient and he realizes - accepts, really -- for the first time that killing Peter will achieve nothing but revenge. Revenge, however fleetingly glorious, will not give him his friends - his life - back.
His eyes burn before he has the presence of mind to stop them; he buries his head in his arms and sobs, fully aware that this time there is no one to stop him from self-destruction.