Advice please - Moms with 3 kids of 1 gender

Ja
Hi - we just found out we are having our third boy in October and I am pretty sure this is our last child.  According to our anatomy scan he is active and healthy.  That should be good news right?  Well I am getting a lot of questions about whether we will try again for a girl or just sad looks that make the congratulations feel much more like condolences.  
I am sure I am not the only one experiencing this reaction.  How do you respond when you get these kinds of reactions?  
I get flustered and I think my frustration with the comments makes it seem like I am disappointed, when I am very happy to have another brother.