***** NOT A TEACHER *****
Hello, English Hobby:
May I suggest something like:
Yesterday I was walking Mutt, my dog, when he saw a cat and ran after it. I looked three hours for Mutt, but I became tired and returned home. And there he was -- sitting in front of the front door! It was one of the happiest days of my life!
HAVE A NICE DAY!
P.S. Here in the United States, many people love their pets so much that they are a "he" or a "she." "It" would refer to an animal unknown to you.