Hi dyardley,
There is so much good advice here already... I just wanted to post because I am only a few steps ahead of you in the process (although I'm with a different country's program). I thank you for posting this message, not only because I think you are very wise to examine your feelings, but also because I think there are other people out there who feel similarly.
We all have different breaking points... and by breaking point, I mean the point where the doubts come crowding in. For me, the paper chase and homestudy process took a lot more out of me than I thought it would. I am very organized, I work from home, I've raised a 9-year-old child... what's a few months of sending away for certificates and being fingerprinted, right? Oh... but don't forget the fact that you will have to have your entire dating, marital, medical, financial, and emotional history revealed to someone you've never met!
It got to the point that I became very combative and was ready to through in the towel at small things; for instance, on the boards, there was discussion that some agencies with our country program do not allow adoptive parents to use their own parents as guardians due to age. Before I discovered that my agency was fine with it, I thought, "What is this? I have to choose people I don't even want as guardians for my children just because they are younger? Well, forget this whole thing--too much of our lives are being changed!" It was silly, a small thing, but in my sensitive state, it was magnified to a point that seemed like every part of our lives had to change. In this prep stage, it's hard to see the child at the end of the journey.
I feel for you and, as I said, commend you for examining your feelings. For me, all of my prep stuff is done and we are in Immigration--the doubts have dissipated. But I think Carolyn made a wonderful point of looking at your life and thinking of what you might do differently if the adoption were not a part of it. In fact, it reminded me of that saying in Algebra, "isolate the variable." Hopefully reflection in that way can tell you if it's the impending adoption that is causing the doubts or another aspect of your guys' busy lives right now.
If it's the adoption, you don't beat yourself up over it. There is never a reason to feel guilty for making a decision that has the best interest of your family and your marriage in mind. Recognize that if you stop the adoption, you will probably grieve a bit, but believe in your decision.
I wish you the best! You are very brave and sound like a great mom and wife.
Christina