What can I do to stop losing weight from depression?

I have been severely depressed for over 6 months now. Whenever I am anxious I cannot eat properly. It is really difficult for me to finish a meal let alone keep one down. I am in therapy but it is a long road.

I have also been really sick for some time(you can read about it in detail in my other post). But basically I have developed some kind of histamine intolerance which makes it difficult for me to eat without having an allergic reaction. I also throw up sometimes after eating because of this. I am trying to get medical help for this but sadly doctors cannot really find what’s causing it.

Between both these conditions I have unintentionally lost around 7 kilos since September. It is not an extreme weight loss but people are starting to notice and comment on it now. My clothes don’t fit me as they used to and I don’t feel like investing in a new wardrobe right now. What can I do, other than forcing myself to eat, to keep my weight up? I would like to get back to my original weight because I don’t feel like myself anymore. Are there any foods or supplements I can take to keep my weight up or gain it back?