Hi Regina,
There are lots of different types of meal replacements. Your doctor might be able to prescribe you some-like Ensure. These are powders that you are mixed with liquids but are also nutritionally balanced so you get enough protein and fats. If you find that you're just looking for something you could just make at home, you could look into:
1.buying or making your own bone broth. Bone broth is very nutrient dense and contains collagen which can help with gut repair. You can make it by cooking bones from chicken or beef over a period of 24 hours or use a store bought option. It can't replace a whole meal but it can be a way of getting some nutrients in liquid form.
2. Making your own smoothies and juices. Again, these can help give the gut a rest but aren't as balanced as the ones your doctor can prescribe you. But if you can't face dinner, whizzing up a smoothie of things like banana, milk (or a dairy free alternative), peanut butter and a protein powder- might give you something to eat which won't require too much energy to digest.
In the first instance, I'd speak to your doctor about prescribing something like Ensure- that you could keep at home to use in an emergency. Id that's not possible, then temporarily focusing on liquid food-like broth, smoothies and juice- might also help.