I didn't have a new baby but this is a little of how it was for me. My DS and DD were six and a half and three and a half respectively and I was absolutely terrified! Introductions had taken place over a horrifying short space of time - on the other hand they had been with a foster carer who, whilst having done a great job, had completely stepped over the line (understandably because they were and are gorgeous of course!) in terms of getting attached to them and it was almost a case of wrenching them from her (literally - her sister had to more or less carry her off). So in some ways I was glad to get on with it all.
I was stressed to high heaven, lost about a stone and half in the first few weeks (seriously - because I was too anxious to eat). Started sobbing when I opened the door to my lovely adoption social worker for the first time about three days later. It wasn't that they weren't lovely - they were - if a little 'high spirited' ho hum! But I just felt the overwhelming enormity of what I had done and I suddenly doubted myself hugely and wondered whether I could ever come to love these two little people - fully formed it seemed at that age - even though I quite liked them - could I LOVE them?
And look at us now - the anniversary of their coming to me was eight years ago yesterday and I now would cheerfully kill for them. And actually, looking back, it didn't take that long. They are wonderful, funny, loyal to each other and to me, loving, exasperating, infinitely interesting, STILL a little high spirited!!!, challenging, beautiful (no, honestly - my son really is, I can say that - as it is nothing to do with my genes!) and adopting them is the best thing I ever did.
So DON'T expect to 'fall in love' the minute you meet your baby, expect all the emotions in the world so be good to yourself, get support not just from other adoptive parents but also just other parents. Some of my best advice and suport has come from my closest friend (mother of four - you can imagine how awful she has felt every time she became, it seemed effortlessly, pregnant with me struggling through IVF, adoption approval etc!). She was able to say to me everytime I got a bit paranoid about it all being down to their being adopted that I was just looking at part of the wide spectrum that is normal. Don't expect to sleep for the foreseeable future because even if your baby is asleep - you won't be - I lay awake just listening for the sounds that were not normal - trouble is I didn't know what they were! There was such a history I had missed out on!
Oh and most importantly - be yourself and trust yourself. Be the mother that you always wanted to be. I had had it drummed into me that it was very important that to start with and for some time after that I kept things the way they had been at the foster carers as it would be unsettling otherwise especially the age my two were. Unfortunately their foster carer was about as far away from me in terms of parenting as could possibly be imagined - even though I take my hat off to her in some ways and, if it wasn't for her, my kids would not have been as settled as they were as they were in a dreadful state I gather when she got them. However, after one Sunday morning breaking down in tears, in all the effort of, on top of everything else, trying to keep to all the 'rules' that she had set - I just went, 'Stuff it'. If these two had been mine from birth I would be doing it so differently and so I let them, for example, run about the house in their PJs for example, I gave them all sorts of 'exotic' food - i.e. not Pot Noodles (that was supposed to be very important, keeping to the the food they were used to but I just couldn't do it!), I let them come into the kitchen and help me cook, I let them do all sorts of things that hadn't been allowed (they were forever asking me 'am I allowed to .....' and I know that as a foster carer - and she was and probably still is a very good one - she had all sort of rules that she had to adhere to - my mistake was thinking I had to as well) and we have been as happy as larks ever since. So - trust your instincts - Lord knows we have been assessed to death in a way that most people who have birth children aren't (no offence PLEASE - don't want a backlash)so we must be able to do some things right.
So much luck and hugs to you - I am quite jealous. My DD would LOVE another sibling but I am too old I fear and my personal circumstances have changed but I wish you all the luck in the world - you are going to have so much FUN!