Freaking out about having a boy

We have 3 girls and we wanted another one. It's a boy this time. What's wrong with me that I'm just not excited? I'm scared and sad over it. My husband odd finally excited but I'm very back and forth. I trust the Lord knows what we need and mostly what He needs, to fulfill His plan but geez it's hard. What kind of mom feels sad over the gift of life? What's wrong with me? It took 5 years to get our 2nd and 7 to get our 3rd and we wanted 1 more before I turned 40 and the Lord said yes! The baby and the boy will only be 18 months apart. It's joy and fear.... We also can't find a name. It needs a "y" in it... We all have a "y".