Disclaimer: Naruto isn't mine
Being a dad means waking up in a cold sweat over the thought of your increased responsibility. This is called "delayed onset maturity."
Gaara took to the news of become a father quite easily it appeared. He was calm and collected, happy but not jumping out of his chair(unlike a certain other emo ninja) in all it was the perfect reaction for Gaara.
That is, unless you saw him at night.
At night Gaara was glad that he couldn't sleep. His dreams would've been better than his actual thoughts. Every night they flooded his mind. Would he have to stop making fun of Kankuro? Would he have stop calling Kankuro an idiot? How would he gently break it to Temari that she couldn't swear? How was he going to break it to Kankuro that his favorite topic of conversation wouldn't be allowed for quite a bit?
Would he have to tell Shukaku to stop being such a horny sadistic demon? Would he have to lie to his child about his grandparents as to not cause mental disturbance? Would he have to read a child-rearing book?
Would he have find a way to sleep to avoid doing work at three in the morning?
Yes, as soon as possible.