Two more weeks of stay-at-home baby bliss

I have two more weeks of maternity leave before I have to return to work. And I'm dreading it. I'm dreading it more this time than I did with Ivan. I look at Ivan and see how fast and fleeting the last three years have been. Allen, being the second child with an older brother to look up to, will grow up even faster.
Their babyhoods are such short, almost elusive, periods and I fear that I will have spent them at work.
Since I know that Allen is the last one, there is an ominous sense of finality. This is it. If I don't pay attention know and aren't fully in the moment, these moments will pass for ever.
And that's when I start to think about maybe going for a third child. This has been at the back of my mind ever since I first held Allen in my arms. I was so painfully aware that his newborn-ness will evaporate quickly and unnoticable and had already started having thoughts of another baby. I thought they would go away by now, but they've been lingering on. Whether it's because I want a girl, a big family or something else, I'm not sure. Except that we're not set up for a third one nor had ever considered it until these thoughful now.
So I'm really grappling with the fact that I need to return to work soon . I do feel lucky that I have been able to take 20 weeks of from work and that I'm returning to a mom-friendly environment and a job I like. But I don't want to go back. I wish I could only work three days a week.
It's funny because I never really saw myself, and still don't see myself, as a stay at home mom, but I have been really enjoying this time with the kids,even though on most days it's rather challenging. I have also acquired/dropped some habits that myself from ten years ago would be appaled at: like not keeping up with the news, not caring to keep up with current events and not reading the paper.