I would suggest tweaking and recording your diet and effects over time. I cut out dairy for a few years among other things and when I tried reintroducing it suffered dreadful depression. I couldn’t get myself to stand up at one point.
I do eat dairy now but quite sparingly and if I have a bit more I notice it effecting me: actually is negative on the following days when I don’t have it/less of it. This makes it harder to pin down but I have.
Might be one to think about. I have no doubt different foods cause issues for different people, it may be when low carb you rely on your depressing foods more without realising it? I’m very interested in gut microbiome health.