I would say at least part of it is being busy with ds. My ds is 2 yrs old and he does keep me busy! I know what you mean though. This pregnancy is definitely different from my first. When pregnant with ds I was constantly thinking of the little baby growing in me, wondering how it was doing, reading books, etc, etc. And with this pregnancy I'll be going through the motions of my busy day, waking up, giving ds milkie, cooking breakfast, doing dishes, driving around shopping, etc, and filling the requests of my 2 yr old. And then I'll go, "Oh yeah, that's right, I'm pregnant". :LOL . In one way I like it, because this pregnancy is going by much quicker and before I know it I will have the new babe in my arms.
But it's also almost like I am still in disbelief that I'm actually pregnant again and going to have a new baby in about 5 months! As the pregnancy progresses I do feel more bonded but it's not in the same way...when you are caring for a little one already you just can't spend as much time doing all those things you did before. But remember, it's not quantity, it's quality. So even if it's just passing thoughts throughout the day, you are still thinking of the new baby in your belly and that's what counts