I love both of mine more than I can express but it wasn't instantaneous by any means.
Now, put down The Primal Wound, which I haven't read either, and go and buy The Unofficial Guide to Adoption by Sally Donovan. Which will make you laugh, cry and if you need it, will give you a real understanding of how to deal with issues which may come. Read also the chapter on Self Care - gold dust.
I do fear that, although understanding of attachment is so important, we as adopters fall into the trap of feeling that we must be working to a recipe to make our children 'attached' and that if we haven't done it in the first six months we have blown it. In actually fact the brain is very plastic, progress is possible at all sorts of points and I think we'd do better to relax and let ourselves get on with what's actually at the root of attachment and comes pretty naturally to parents who have been well parented themselves - loving the child, responding to their needs, interacting with them, helping them regulate their emotions.
Anecdotally - I was massively over anxious with DC1, read everything, slung him, co slept, bathed him, etc etc etc. He's a delightful eight year old with significant attachment issues.
DC2 arrived a little bit older and I had no time to read the books. She went to nursery because, well, she had to. She shared attention with a demanding older brother from the off. She is a delightful, secure, socially skilled and high achieving six year old.
Possibly the conclusion from that is that I should not get over involved in parenting my children 
But also that, as with so much about birth children, only a certain amount is within your control. There's a lot to do with what they bring to the party!