It is very possible to give your child up for adoption, however in this country it is not an instant thing. Initially the child will live with fostercarers (who may or may not be approved to adopt as well), and you have 16 weeks in which to change your mind.
I have worked with a number of severely disabled babies who have come into the care system. Some have gone back home to birth parents once the birth parents have worked things out for themselves a bit, some have gone on to be adopted or at least to look for an adoptive placement.
I don't think the OP has been given a fair hearing. Yes, those of us who have severely or profoundly disabled children do know how good it can be, we know how much we love our children and we know how much their siblings have benefited from having them in their lives. But there are some birth families who cannot commit to their child with a severe disability, just as there are some birth families who cannot commit to the child without a severe disability. It's entirely natural I think to be worried about it, to wonder how it will work, to be scared of the possibility, and to consider the future. Sometimes just knowing that there are options out there means that you can carry on yourself because you know it doesn't have to be forever - knowing that there's a number you can call and say "enough" means that you don't have to make that call.
A look at the number of severely disabled children who are adopted ought to indicate that there are a significant number of birth parents who make the decision not to parent their child. I don't think that makes them all monsters at all - and fwiw I definitely think it's better to have the child and go for adoption then to abort. But that's just me.
Oh - and as far as OP being a troll because only one post - look at the kicking lots of you have given her - wouldn't you be inclined to namechange if you were making that original post?
To the OP - call your local social services and see what they say - they may have more information, and they may also have info on support groups and other services they can offer to families who do have a child with disabilities; it may help to know you wouldn't necessarily have to do it all totally alone.