Sirius tried to recall how long it usually took Lily to calm down when she was this age. He forgot sometimes that she was younger ... not that those three years suddenly stopped them from arguing, but still. He knew he'd gone about it the wrong way, but he was just baffled that she would want to spend any time at all with Snape, let alone go to the bastard's place by herself.
He also knew that he was being even more over protective than he usually was, but it had only been a few days since he'd seen her dead. He thought he was entitled to a little protectiveness.
After spending some time with Remus and cooling down himself, he left his friend's room to head back to Lily's. If she wasn't ready to forgive him, he would spend the night with Moony, but he hoped she had at least calmed down enough that this visit didn't end with them hexing each other.
As he walked through the hallway, he glanced around and behind him to ensure he was alone and then shifted into a large black down. Shaking out his fur, he padded the rest of the way to Lily's room and then sat down in front of the door. He barked once, sharply, and then let out a long, mournful howl. Honestly, who could stay mad at an over-sized, apologetic dog?