I feel your pain on that. It is SO hard for me to get calories in the tummy because I feel sick when I eat. It may be low stomach acid - check with your doctor if you can go. It may also be partly psychological - I know that for myself, my mood will vastly affect my appetite and digestion. If you're in therapy along with the Prozac, and it's good therapy, that will help. If you're not, or even if you are and would like to take it further, try reading a quality book as a kind of substitute. Get a recommendation from your psychiatrist or therapist, or try "The Feeling Good Handbook" by David Burns. It is strict REBT (Rational Emotive Behavioral Therapy) based. I don't want to go too much into that, check out the book on Amazon or something if you like, but REBT for some people, including me, is the best thing since sliced bread (tee hee)!
Now, for dietary solutions, I can share what helps me and it may help you out. If you can do dairy, I would recommend lots of milk. When I can't eat, I can still usually drink, and full-fat (raw if you can get it) milk has tons of nutrients and will help get calories into you. I drink at least 2 gallons a week. A second thing is probiotics! The more good bacteria you have in your tummy to help digest things, the better. Fermented vegetables, kombucha, yogurt, milk or water kefir are all great ways to get the good stuff, and all these things are easy to make at home and inexpensive. Lastly, bone broth! It usually goes down easily, it is very nutritious, you can make soup in it with the meat and veggies (chicken bone broth with kale, chopped tomatoes, onion and garlic is one of my faves!) and all that gelatin can help your tummy.
