I think you’ve already done an exquisite job of explaining yourself and the tie that binds you to those books. You know those books aren’t people, but throughout your life they’ve comforted you as if they were a best friend or parent. You spent a lifetime building a collection you loved and many were gifts from people you have loved. I can’t imagine how difficult that would be to part with…. But still, when the time came you did what you had to do. I’m a bit of a collector myself. I, too, am an only child with no kids of my own. And I, too, attach emotional significance to objects. So, I understand, believe me I do! :
We attach memories to objects, but they are not the memory. You still have your memories of those stories and of the precious moments those books were given as gifts. You haven’t let go of the comfort they’ve provided you. You’ve merely let go of their physical presence, which was a necessity – not a dismissal to their impact on your life, or a dismissal to the wonderful people who gave them to you. You will always have those moments in your heart, so they don’t need to collect dust on a shelf.
You already know that, and knew it when you parted with them. You’re confronted with many new things in moving, and you’re going through a period of adjustment. You no longer have the stress of the actual move to keep you occupied, but you’re still confronted with the major changes that you’ve made in your life. It’s natural to want to reach-out to the things that have always brought you comfort and miss them.