Being a Pet Parent

I'm not usually one to consider a pet as a full fledged member of the family. We had several dogs and cats growing up and while I loved most of them, they weren't really family members to me.
This last weekend Oscar, our 7 1/2 month old puppy started acting like something was wrong. He stopped eating and drinking and was very lethargic. Well, yesterday we took him to the vet. Thank heaven we did, he had a solid and sharp obstruction in his bowel that was blocking everything. So, yesterday evening Oscar went in for surgery and according to the vet he came through just fine. He did well last night and during the day so at 4:00 this afternoon we finally got to go pick him up and bring him home. It was so odd, leaving my little guy there. He was so happy and sweet, like he always is, and I felt like I was abandoning him. I hated the idea of leaving him. We went to dinner and I could not get my mind off him. I have been so worried. And at the time I was just worried about leaving him at the vet overnight, not the surgery. We had been told that the surgery wouldn't be until the morning. It was actually nice to get the vets call last night telling me that the surgery was already done and that he was waking up before I even had time to really worry about it. Still, our home felt so empty and we could not have been more excited to have him home.
Anyway, my point is, I don't know when this happened to me. When did this dog become a child to me rather than just another pet? I couldn't say when it happened or how. All that I know is that it did.