I think being on the diet can affect us in different ways emotionally. I had a day in my first week when I was really bad tempered, which is unlike me. I think maybe it amplifies our emotions so if you're prone to depression it can make it worse. But, I only had that one day and I've been fine the rest of the time, so hopefully it's only those first few days while our body is aclimatising to the new regime.
This may seem like an obvious question but have you talked to a doctor about the self harm? I guess it depends on how it manifests. I kind of self harm too, but not in the usual way of cutting, I just make myself bleed by picking at hairs on my stomach til they bleed & then keep picking the scabs constantly so they dont really heal or scar badly. I know you're not sure about counselling and you're going through a lot at the moment, but what about medication? Anti depressents and anti anxiety medication really can help, please dont leave it if it's getting bad, it's not a weakness to take medication to help and while they wont numb the feelings, they wont feel quite as overwhelming as they may do now.
Sending you lots of hugs in the meantime x