My cat has gained a lot of weight and become reserved since you had your dog put down is this normal?

Cats can react to changes in their environment, including the loss of a pet, in a variety of ways. Some cats may become withdrawn or reserved, while others may become more outgoing. It is common for a cat to gain weight if their activity level decreases after the loss of a pet as they may turn to food for comfort. If you are concerned about your cat's behavior or weight gain, it is best to consult with a veterinarian.