Moms of older babies - do you ever feel like this?

I can honestly say without hesitation that when my firstborn, my daughter, was born it was the happiest time of my life. The world seemed to GLOW! She is almost 20 months old now and I find myself thinking back a lot and reminiscing but it makes me sad - that it went by so fast. It seems like just yesterday I was holding her, a tiny newborn, in my arms and now she's running around, talking, ''reading'' books and just growing up so fast! I also had my son back in October (they are less then 12 months apart) and time seems to be flying by faster then ever. Anyone else ever feel kind of sad and nostaligic about those early days and months of their first baby?