I lost my first beloved Yorkie (Ivy Lucille) several years ago. I was devastated. She was my first "child" and I loved her like one. I won't get in to the whole story of her death but in the end, I had to decide to let her go. It tore me up. I was physically ill as we went through our last day together. It was a long time before I could look at pictures of her or her baby teeth. I had cut a lock of hair from her on the last day and tucked it away.
It took me a few years before I could even consider getting another Yorkie even though I longed for her. I finally missed having a little dog around so bad I finally got my Mayzie and then my beloved little Mozes. I often think of the pain that I will inevitably have to endure again and it scares me to death. But I can't imagine what I would have been giving up if I had not gotten either of these guys. They bring me so much joy that I am willing to face that again. In some ways, I think it will be a LOT harder now because at the time of Lucy's death, I had young children to occupy my time and now my kids are teens and I am fully invested in Mayzie and Mo.
Sorry, I have gotten long winded here--my point is this: While losing them scares the hell out of me, I try not to let that fear sap my joy that these little guys bring me every day. While I do think about it--to often actually, I try not to think about losing them, when I should be enjoying them while I have them.