So, I'm 100% certain I want at least 1 more baby, maybe 2. But when I think of another baby in the house, I'm often just, like, "meh." Someone one said (I have no idea who, but it was in response to the exhaustion of having little kids): envision what you want your thanksgiving table to look like. Or, for me, I envision who I want around me when I'm old, too. "Get this baby show on the road" Ahh just the way you said all this resonates so much... The early months with DD were a little atypical due to here being premature, in the NICU, me workin alot, my husband being a SAHF, me exclusively pumping while he took care of her, etc. maybe everyone feels this way but I love her a lot more now than I did then. But I also think part of the "meh" comes from whatever is in me that made me work in high-intensity healthcare setting, maybe similar to you. Not to say that ICU nurse = callused or unemotional, but, I don't know, there's something different... I spent a lot of time thinking about this while being with DD in the same hospital where I had worked and done clinical rotations (not the NICU itself but related areas). I just know I'm not going to react the same way as someone without a very medical/nursing background.
So, nothing is wrong with you! Or at least I refuse to think that because then I would have to assume there is something wrong with me too!