It wasn't the bed nor the weather that was snatching the sound sleep from him. His bed is possibly the best one in the whole residence as he held the highest position in the clan. The servants have made it very comfortable to please him and his perfectionist side. Besides, they are aware of all the combat he has gone through (either it's against a formidable enemy or a one big pile of paperwork) so they made sure that sleeping time for him would equate to genuine rest and heaven in hellish "earth" (soul society, that is).
The weather cannot be blamed either because the wind coming from outside, penetrating through his doors was gentle and not harshly cold, cradling him safely. It wasn't too hot despite the thick blanket which covered the entirety of his body. The light illuminated by the candle was not bright enough to bring discomfort to the Kuchiki head's eyes; everything was set up perfectly for sleeping.
She stole his peace of mind.
Byakuya had admittedly given up to that. The little girl—no, the young lady who he welcomed into his home upon the request of his late wife, had kept his thoughts in disarray.
He has broken the rule twice. Not this time, he swore to himself. However, he know how dangerously things could turn out to be. It wasn't her fault, it wasn't another person's fault—it was his. He let his guard down without him knowing it in the first place. How was his heart, which closed itself from warm feelings of love, able to welcome emotions like that again? Ever since Hisana's death, Byakuya firmly believed that there was no chance for him to love again.
Yes, he might be falling in love with her. The sad part is that what he feels for her might be the biggest menace ever not only to him, but to the reputation of the entire clan as well. He had disappointed and stained their family's name when he married Hisana, did it once again when he adopted Rukia and now he's about to—No, I'm just confused, he kept convincing himself, his head full of thoughts ready to blow his brains off. The feeling is pure danger. He knows the society will condemn him for what he feels towards his adopted sister.
The society—what do those people know! Byakuya was now fully awake. The things he fear were now right in front him, presenting themselves as shadowy figures and people who whisper to him that he should let the feeling go. The uneasiness he felt became stronger as the time passed. What does the society have to do with us? He started to question the social environment in which he lived. Who are these people to judge me and what I feel? Why do I have to maintain this reputation just for their recognition of our efforts? What do their opinions have to do with us? Why do they judge so quickly and harshly?
… And most of all, why would I let them get in the way when all I want is happiness with her?
Byakuya was enlightened upon attempting to understand the questions, not only answer them. He was now fully determined to go forth as his undaunted soul is fuelled by his desire to be with the one he loves. Tomorrow, she'll be the first person to know what I'm feeling—I'll bring her flowers, tell her how much I love her. I know that after my confession, she'll have her face painted in pure disbelief, but I'll just kiss her and tell her that it's all real.
I do not care how people will see me. I do not have to put up that cold front everytime I'm around them. I do not have to be the Byakuya they expect me to be everytime. I am free when I do not become the self that society has dictated me to be. The real Byakuya is ready to take the risk in order to fight for what he wants.
The young man has realized that the peril here does not lie on his love for her, but the danger of being judged and condemned by the people who surround them. Nevertheless, the disastrous results of his actions (which are not impossible to occur) does not discourage him from having the girl he wants to marry. As peace and comfort suffused his mind, his eyes closed, ready to open and accept the reality tomorrow.