First let me say that what you are feeling is very normal. It's a big step. It's hard to get really excited as you are not the one who is carrying the baby or feeling the internal kicks etc. But once the baby is born and you get more hands on experience, these concerns fade away. And you then become a proud father.
Some people deal with change just fine while others it does take awhile. And having a baby is a big change in life. You are correct, there is so much more responsibility, it's hard to come and go like you are use to. As now you have to plan where to go and what time to be back, as there are feedings, diaper changes etc.
But in no time you will get use to it and wouldn't change it for anything. So try to relax and know that what you are feeling is normal and it's really only temporary. Once you get closer to the due date, you will start to get excited and will become more prepared.
Keep in mind you can only prepare just so much, but once you see the new baby, all that will change and most likely those feelings will be replaced with the new feelings of how real it all is. And how you wouldn't change it for anything.
It would probably be more of a concern if you didn't feel the way you did. Especially being a first time Dad.
I wish you all the best and congrats to you and your wife.
I hope this helps see things from a different perspective.
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