I am another one who has a DS with CP. He is now 10. I love him to bits (even today, mid lockdown). I remember some of the other posters as they first posted with their stories and their fears as they were warned about what might come, coupled with the we don't know. And largely it is the we don't know that is the hardest to hear, but sadly true, they don't.
My son is in moderately affected. He will always use a wheelchair. That is worse than the prognosis we were given for the first 2/3 years. Telling you it will be ok isn't always the right thing to do. It might not be.
The wheelchair is a pain, but a pain for me not him. For him it's freedom (from me!) it's how he gets about without me.
I am not going to pretend life is easy, or that I don't still feel envy of friends with "normal" children. It also made baby groups impossible, I walked out of one when a midwife said whatever you are going through someone else will be feeling the same thing. I don't think so ! I did not fit special needs groups either. In the end I went back to work and that was the best thing for me. It stopped me worrying.
Take every bit of help offered. It is helps great. If not don't do it twice. And that should be help for you and your DH as well as your baby. If someone asks what they can do let them do something. I never loved my own mother as much as the day she let herself into my house (she has a key) and cleaned up the baby sick over the floor without even asking, so I could deal with my son.
Take portage/physio/ot and if you need them antidepressants for you.
Take time with your husband. He is grieving too. Families of disabled children have shocking divorce statistics but those who stay together are usually stronger. Talk to each other even if it hurts.
If you think the hospital was at fault talk to a lawyer. I didn't think they were in my case, but you need to work out what you think before you can learn to live with it. And if they were at fault take action because it is expensive having a disabled child (sorry but it really is!)
When they first mentioned CP to me I was in shock, then grieving. I spent years trying to make my son fit in and get him to walk. For years that was the goal, but now that he is older I have realised that it doesn't matter. (See my comment about wheelchairs above).
If Facebook doesn't help stay off it. You wouldn't know my son was disabled on my Facebook account, I have never said. Not because I am hiding it but because that is not what I use Facebook for. You'd know if you follow me on Twitter though.
There isn't a right way to respond, a right thing to feel or to think. We all find our own way. It takes time and it is ok to not be ok about this. You just have to hope that one day you will be more ok.