I felt exactly as you did when I found out I was expecting a girl at my 16 week private gender determination in my last pregnancy. I always, always wanted a boy, I tried to keep my feelings to myself and didn't discuss my preference with my husband, but like you, had a bad relationship it's my mother and felt a boy would be more special. When they showed me those three lines I about died inside. I wanted to bawl my eyes out right then and there but I pushed the sadness away and just tried to get on withit. It didn't help the right after the scan when my dh called his mother, she was so bitter and unethusiastic because she wanted a boy...she said girls were winey and difficult and I think right then and there I snapped out of it, I suddenly felt very defensive and protective. We told her the name on the phone and she made such a huge commotion and couldn't hide her dislike of our choice, I did burst into tears. I think the whole of the pregnancy I felt disappointment, my friends were expecting boys and I was filled with jealousy.
I gave birth to my little girl and I have to admit, it affected my bonding, I didn't bond immediately, it took a few weeks but them as time passed the love just blossomed and grew. I see her with my husband and she IS his absolute princess, I don't even see the gender anymore, she's just, the child we were destined to have. I adore her, so much so, when I got pregnancy again,I wanted...ANOTHER girl, as soon as I got my bp, I washed all her beautiful baby clothes and hung them up, I never even looked at a boy outfit. Then at my 20 week scan, it's a boy they said and I think my heart broke again, for the opposite reason. Lol.
I'm still not as enthused about having a boy as I'd like to be. I know my daughter is thrilled, my husband I think has apreference for a girl, but he's excited, my mother in law is oer joyed , so much so, it sickens me, I detest her blatant favouritism. I'm confident that my feelings will again resolve as they did with my daughter. People tell me, oh you're so lucky to have one of each, you're done now, even asking if I'm having my tubes tied...I still think hubby and I will want to try for another girl. We always envisioned three daughters, now we need to make room for a son.