In way everyone that goes through a traumatic existence experiences survivor’s guilt. I know I have. Tonks did when Padfoot, I mean Sirius, was killed by Bellatrix in the Department of Mysteries and, like me, her metamorphosing became very unstable for a time. I think EVERYONE who survived the Battle of Hogwarts felt it.

I don’t know how to describe it because it is more than loss, missing someone. That is grief. It is the fact that you did nothing in order to stop the “event” from happening. You survived. It is different when people die of old age or from an illness but when they die in battle it is common.

It is described as a mental illness but I have never liked that term. Why do you get it? Because you are human, you have experienced something traumatic and it takes time to realise that it wasn’t entirely your fault. Nobody ever wants to listen to that sort of thing but working on it helps.