Gender disappointment

Please don't comment unless you are suffering from gender disappointment      or wish to offer emotional support.
I wanted a girl and am having a boy. I am sure I will love my child and he is still wanted but I am grieving for the girl of my imagination.
I am happy and greatful to have a healthy child growing inside me but I am disappointed not to have a daughter.
I feel ashamed and guilty about feeling any sadness at what is otherwise a very happy time for me and my husband.
But my feelings are real and stronger than I expected.
I went shopping after the scan and bought a beautiful soft baby blue blanket with dinosaurs on it to help me picture my future with my baby boy.
I need to start reimagining my future. 
Please tell me if anyone of you has experienced this and what conciliation you were able to find in time.