Violet, I am so sorry for your loss. Nothing I can do or say can ease your pain right now but I just want you to know that you and Roxy are in my prayers.
When I lost my dog in January, my other dog would not eat for two days. When my grandmother died, my aunt (who grandma lived with) took their dog to the vet because she was not doing well. He said that they mourn just like we do.
Just give Roxy lots of love and some time. Try hand feeding her. She will eventually eat again. It's only been two days. Maybe if you're really worried you could call your vet and see what he or she says.