K.--it's been two years since I lost my baby brother, my first "child." My mother had six very close together, and "gave" him to me (she did it jokingly but I took it seriously, bonding as if he were my own). I have three of my own now, but the comparison between my real children and my brother only serves to prove to me that he was "mine."
I can't take his phone number off my cell phone, I can't take his name off my "skype" list. I cry often still and it's been two years.
There have been some good things. I've developed a relationship with my only sister that I never had before, and that's a gift. But I'm a writer and tend to research my feelings to figure them out, and all the psychology literature says to look for ways you can grow from the experience. Hear me out. :) It's hard to think that way. But resilience studies constantly reinforce that if you're going to come back, you need to think of something that his loss contributed to the world. Maybe it made you more empathic so you can identify with other people who have lost their children. Maybe it made you connect with other people in your family that your daughter naturally overshadowed with her wonderful personality. Maybe one of a hundred other things, only you will know.
One thing that helped me was making a memorial page for my brother on "Facebook." I invited several of his friends to hook up as "friends" on his page, and gradually others have joined. I invited them to add photos of his life and post special memories of him on his wall. His friends sent me so many photos and so many anecdotes that I began to see what a wonderful life he had and how many people he'd touched--that has helped me more than about anything.
Sorry this is so long! I feel for you though, wish I could help. Thinking of you and wish you all the best.
G.