When a person prays and is not answered, he should not give up. One of the reasons why we pray is not to change G-d’s mind, but to change ourselves. The Chovos HaLevavos states the reason we pray is to realize everything comes from G-d. When we realize everything is dependant on G-d, it changes us to a different person. Therefore, since we are now a new person, a negative decree issued against us is no longer valid because we are no longer the same person.
4. Be kind to yourself. Speaking badly even about yourself is unethical.
הלכות שמירת הלשון 