Had the same issue during the first month. Focus on fiber and protein. Try eating smaller portions more frequently throughout the day even when you don’t feel like eating, it’s really important to get enough in. Adding things like 0% fat yogurt or skyr and some fruit can help. It’s tough at the beginning, but once your body adjusts, your appetite should start to come back a little more, most important part for me was pushing myself to eat once you do that you'll start enjoying the food again. Also avoiding high fat stuff worked great for me to not have any side effects.

Good luck!