Bone broth i.e. chicken soup. Use any leftover bones you have (beef bones will add a lot of good fat), and boil them for a long time with some sea salt. Add some ginger to calm your stomach even more. You can add some veggies too, but if you're having issues with solid food, don't eat the veggies. The idea is just to extract the minerals and nutrients. Keep drinking this stuff until you feel better.
This seems counter-intuitive.. but since going paleo I've found that canned fish (tuna, salmon or sardines) is actually comforting to the stomach when it's feeling a bit off. I find myself reaching for a can in the same situations I would have looked for crackers or toast before.