Sherlock's walk was not nearly as relaxing as he would have liked it to be. In fact by the time he returned to his apartment he was even more agitated than when he had left. The sight of April had worried him. He spent most of his walk trying to think of all the possible reasons that would cause such drastic physical changes in a person. Yes April had been sick, but had she really been that sick? If so why hadn't Charlie called a doctor, or asked for John to go and look in on her? Charlie and John were very friendly, it wouldn't have been odd for Charlie to make such a request. Maybe April had rejected help, maybe she was afraid of doctors?
Suddenly Sherlock had a terrible thought. One he immediately tried to shake out of his head. It was wild and couldn't possibly be true. It wasn't even possible to entertain, but yet it snuck its way in. What is Charlie was the reason April looked that way. What if he was the reason she wasn't eating and hadn't left the apartment in months. It wouldn't be the first time Sherlock had seen something like it. A jealous partner finding out about the other's affair, snapping and harming the cheater. He'd seen it before, but Charlie?
Sherlock began to go over every last encounter that he had had with Charlie over the past few weeks. Nothing had seemed out of the ordinary. He had seemed to be acting in a completely normal way for him. When he mentioned April's illness he had always seemed to be genuinely worried about her, but then abusers were known to be good at hiding their abuse. No, Charlie wasn't abusive, he couldn't possibly be…right? Stopping midstride Sherlock turned and headed back to his apartment. If he was lucky Charlie would still be there and he could observe him more, this time looking for something more specific.
Even though he had hurried, by the time Sherlock made it back to his apartment Charlie was long gone. John had cleaned up their drinks and headed off to bed. Clearly he had ended up taking a much longer walk than he had intended to. Knowing that his mind would not rest in its current state Sherlock began looking through a small stack of John's books hoping to find something that might help calm his worried thoughts.
Sherlock stayed up all night reading through some of John's medical texts looking for something else that would explain April's appearance and replace the horrible thoughts that had settled so deeply into his consciousness. His eyes darted from page to page until in the early hours of the morning he could hear heavy footsteps heading out of the building. Walking over to the front window Sherlock saw Charlie just outside the building in workout clothes stretching before what was obviously his morning run. Sherlock watched until Charlie was well out of view and then began to head to his door intent on going down to April's apartment to ask her point blank what was happening and to get her out of there. He had his hand on the door knob before realizing 1) that it was dawn and April may not even be up and 2) she very clearly did not want to talk to him about anything.
Letting go of the knob Sherlock walked to the bathroom and threw some water on his face. He had to let this go. He had absolutely no proof that his wild thoughts were even remotely true to begin with. As he stared at his dripping face in the mirror he finally began to think clearly. April had probably just been very ill and a doctor had probably come by when he was out. He knew that was the most likely scenario to have happened, and that it fully made sense. Still he had stayed up all night trying to turn Charlie into some evil villain. Hell he had been ready to rush downstairs to save April from Charlie as though she were some sort of damsel in distress and he didn't know why. Sherlock had let his imagination run away with him, something that very rarely happened, if ever. Suddenly Sherlock was very, very tired. He trudged into his room and laid down on his bed, staring at the ceiling until he gratefully fell asleep.
Not long after he fell asleep, Sherlock woke to John banging on his bedroom door.
"Sherlock. Sherlock! Wake up. We've got to go. Lestrade called. Come on."
Sherlock groaned and dragged his still very tired body out of bed and still in his clothes from the previous day left with John to see what the Detective needed.