Self-pity strikes me as when you assume everyone is against you, you can't do anything, etc., etc. What you can do when you feel this way is challenge the assumption. One good way to do that is to write down the distorted thought and then write out a challenge to it. For example, your distorted thought might be 'the whole world hates me!' Then you challenge it by saying 'the WHOLE world?? the world doesn't know me'and try to bring your thoughts to a more rational place.