Sometimes, if he closed his eyes and listened enough, he could almost hear Sirius laughing. Out of the corner of his eye, sometimes he though he could see Sirius. Sometimes, late in the night when a nightmare would wake him, he thought he could feel Sirius' arms around him.
He always thought he was losing his mind. Sirius was dead, he reminded himself, and no matter how much he wished differently, that would never change.
He didn't mind his insanity, because it was the only thing that allowed him to make it through day to day when parts of Sirius were still slipping away from him. For a month after Sirius died, he refused to change the sheets because he could smell Sirius' shampoo on the pillows. The scent had finally faded, and Remus had been almost tempted to wash them in the shampoo. The logical part of him decided on regular detergent.
He hadn't swept because there was dog hair on the floor. He broke down every time he pulled out the broom, and he'd really lost it when Tonks unknowingly cleaned the house.
Snape found him one night flinching as the portrait of Mrs. Black screamed every obscenity she knew at him simply because Sirius had inherited her eyes.
While Sirius hadn't been able to stay in the house, Remus couldn't bring himself to leave. Even surrounding himself with Sirius, pieces were falling away. Sirius, even in Azkaban, had always been so much a part of Remus that he didn't know who he was without Sirius. And the little pieces of Sirius that were falling away were also little pieces of Remus. How long until he had nothing left?