Irrational fear, almost like a phobia. It sucks. Especially when it prevents you to join your birth-family for Xmas due to a slightly unusual and strained relationship.
Hell of a situation to explain "No, I can't join you because I have an irrational fear of the situation and I don't know what would happen if I did." when everyone expects you to be there.
Instead sitting at home watching 'Alive'.