Be patient.. it will come back.. Hydrate, eat things that are dense in calories and nutrients.. I like a hard boiled egg with ketchup when I'm not hungry but must put food in stomach.. or crunchy peanut butter. Get some protein.
And in advance, some advice for when the appetite does come back, eat whatever you want. A lot of people crave sugar like crazy, I did, I just went with it until I got a foot hold in my sobriety, then restriction of sweets was easier to tackle.