Hi, welcome
I had my dd at 43, after years of fertility treatment and miscarriages....it was our 'last attempt just for peace of mind' cycle, I couldn''t imagine it actually working, IYSWIM.
And even though I was pregnant as the result of a conscious decision to try to be, I felt very ambivalent at times - and very scared too. I think both feelings are totally natural even for those who haen't been through IF. I suspect that most first time Mums, if they're honest, have ambivalent feelings at some point...and fear. After all, your life is changing, your body is changing, there's a giving up of control that happens thats enough to scare the pants off most of us!
Although we hadn't quite accepted a childless fate, we were very close to it. So I can imagine how much more shocking it must be for you; I had passing feelings of total outrage that I was actually pregnant after working so hard to grieve that I couldn't be - its all very complicated, and confusing, after years of IF!
Now, I have a happy, wonderful, nearly 3 yr old dd and am 33 weeks with my second and last (was 45 when I got pregnant). Its great, and its scary, and its tiring, and I have had just about every passing feeling in the book at some point. I'm sure you will, too.
And for what its worth, feeling nauseous is the pits: I had moments of loathing my longed for baby in that pit of helpless sickness called the first trimester, and feeling guilty in spite of 'knowing' in my head that would pass. I just wanted to feel better, have my body and my relationsihp with dd1 back as it was, etc. All just feelings - they pass! As did the nausea, and I really hope yours does too, and soon
As for feeling motherly, I don't think I did first time around till I had dd in my arms. Its great that you've posted, glad you found MN, and do just keep talking about it all - it'll be ok, I bet you anything you like. xxx