When I get so depressed that I'm not eating I do the Ensure thing. I also eat WildBerry LifeSavers, something about the sweet/sour of them triggers my appetite and I can eat a little bit. Not overly nutritious, but I eat croissants with fruit flavored whipped cream cheese. I also try to eat at least one container of yogurt a day, usually with a bit of granola.
Are you taking a vitamin/mineral supplement as well?
Good Luck! I think you have try different things and see what works for you. I started with vitamin enriched mineral water and protein bars, and went from there until I figured out the foods/drinks I could keep down easily.

(((((((HUGS))))))) Queen Mab