It's okay to feel that. I believe that every creator usually loves their character in some ways and not everyone is the same. In the end, an oc is just your creation and you can do anything with it.
Well, in my case, since they are my creations, I feel attached to them, mostly with the ones that I created a long time ago. To see they "grow" as the project or the story progress. Especially when you found your old drawings of your characters and compare with the new ones, it really feels like they were "growing".