I Adopted A Dog From A Rescue In VA And

I adopted a dog from a rescue in VA and I live in NJ. When they originally rescued him he did not eat for 3 days. He traveled 6 hrs. To get here and will to eat or drink. This is day 2 and he has not eaten, drank, or gone out to do his business. He just lays in his crate and doesn't lift his head. I think he is depressed over leaving his foster parents whom he was with for. 5 months.
What do I do?
I tried very good treats and homemade chicken.
Help