Hi, OP. I feel for you and what you are going through. None of us can help our feelings.
I have one of each. DS 3.5 and DD 1.
I think deep down I wanted a DD but it didn't become apparent until I was PG with her at the 20 week scan and they asked if I wanted to know the sex. I suddenly felt terrified that if they said another boy Id spend 20 weeks feeling sad.
I honestly wasn't aware of the feeling until that moment.
I decided to wait and spent the next half of PG talking myself round to being happy if it was another boy.
When she was born I can hand on heart say I felt no different to the elation I felt when I had my DS, it was a baby!!
I didn't even ask I just registered the midwife mention it and no more at the time.
Also (this is going to sound awful)...
My son was/is beautiful. As a baby he had blonde ringlets, huge pale blue eyes and olive skin, rosy cheeks. He looked like a cherub and I was always tempted to stick a little hair clip in
!!
He also looks more like me (im much much less cute though)!
My DD is more plain (horrible mum icon).
Straight dark hair. Very pale skin and looks like my DH's sisters who are 
Now this is all very shallow stuff but I guess what im trying to say is, I think we have an image of what/who our DD's would be and it's wrong. They can't be a built up image of a person who doesn't exsist IYSWIM.
I think woman (NOT ALL) are probably more drawn to have a DD and men a DS but it is irrelevant in the end.
My DS is gentle, affectionate and well behaved (sometimes).
My DD is wild, mad (hilariously funny), never ever takes a telling and bloody hard work.
I now realise I had built up an image of what it's like to have a DD without realising it and it's all nonsense.
I know now that id love any child whatever the gender but if id have had another boy id have maybe have held onto the image of this little pink angel who doesn't exsist!
I think there's more chance of my DS visiting me when im old than my little tomboy!
I love them both dearly but I just wanted to give you an honest (awaits backlash) opinion of having both genders.