I am soon going in for surgery how can I keep my dog from getting depressed?

I have to get ACL surgery done soon and my girl dog JAZZ is a mommys girl she only wants me to feed her take her out ect. My b-friend works durning the day and has are other dog at his home. So its not like he can take her out for me. My mother is sick and she cant help much and my sister helps my mother and is NOT a dog person. Now I sit outside and play ball with her but when I go for surgery I am not going to be able to get up and play with her the way I do. Im afaird she will get depressed and fat. Also she is snippy with strangers so what should I do?