Gender Dissapointment

Kristen
Four weeks ago my doctor gave me a scan and told me I was having a girl. Which is exactly what we had hoped for (this is our second) as we already have a daughter.
Then at my anatomy scan last week it was evident I'm in fact having a boy! 
I'm finding it really hard to get my head around it and finding it hard to get excited now. 
Don't get me wrong I'm so relieved my baby is healthy and I feel very grateful regardless. 
However I'm feeling the pang of gender Dissapointment and also guilty for not being as excited as I was the first time. 
Please tell me this is ok and I will get past it? 
I think I'm still in shock to be honest.