Loving your other pet/s after loss

I lost my puppy and I’m having trouble showing genuine affection and love to my senior dog. It feels forced and fake. Everytime I look at him I think “she should be here with us”. Or “i should be walking two dogs, not one..” I feel robbed. I feel angry. It’s unfair. Everywhere I look I think of her. Is it just me? Has anyone else felt this way?💔