Ok firstly, congrats on the pregnancy
Secondly, your worries are perfectly justifeid. It's bloody scary becoming a mum. I have a 7mo dd and I've only just seeked attention for the troubles I was having, turns out it's PND! I always wanted to be a mum at some point in my life, and thought it'd be the best thing in the world. And whilst it may be for some, it isn't always the same for others.
I had never held, changed or fed a baby in my life until dd came along! Honestly, you stop thinking about the 'how the f**c do I change a nappy?' and the 'what was it the book said again?' when they're here, you just get on with it.
I felt I loved my dd throughout my pregnancy so I didn't feel that 'rush' of love when she was born, because I had always loved her. Does that make sense? I love my dd dearly, but admit to struggeling. I have problems with myself, not with her. PND affects all women differently. A lot of women don't get the rush of love, some do. Don't fret about it though.
I think the only advice I could give you is just take it a day at a time. Try (and I know it's hard!) and not panic, because a lot of the time, you're worrying so much that 9 months fly by and BAM, you've got a baby! Have a day off each week and totally relax, be completely selfish and eat as much as you want lol!
If you are worried I would say speak to your midwife, they're usually so good and helpful. But please try to stop worrying about months down the line. Enjoy the now with your bump, because you'll never be pregnant with your first child again. Just try to enjoy it
Motherhood isn't all sunshine and buttercups like the glowing women demonstrate in the pg books, seriously I'd burn them all if I could - useless! It's tough, but it can be ruddy good fun too