I have heard this is pretty common for your second and any subsequent pregnancies. I think maybe because it's not really a new experience anymore. You already know what to expect and how things work, so the fascination and wonder isn't as high as it was with your first. I feel the same way. I think it's because with my first, it was just me and my oh and the baby in my belly and it was all I ever thought of, talked about, dreamed about. But now, I have a toddler, and life doesn't just get put on hold like it kind of seemed to with my first. I still work full time, I still have to chase around my 2 year old, none of that stops or slows down to give me time to really think about the little one in my belly.
I have just recently started feeling flutters and I really like that because half the time I forget I'm pregnant just because I have so much else going on. The flutters remind me he/she's there and I can't wait until they get stronger and more consistent. With my first, I loved knowing she was in my belly and that she went with me everywhere I went. I always had my hand on my belly out of just natural habit without really thinking. I'm not one to really "talk" to my belly or anything but I did love knowing she was always with me. I don't feel that at all with this one, at least not yet anyway. But sometimes when I feel bad about not feeling so in love with this one yet, I'll watch like Baby Story or some kind of show about pregnancy/birth/newborns and I'll get all emotional and excited again LOL.