Traumatic events such as natural disasters like earthquake, floods etc. can give rise to a characteristic pattern of psychological symptoms. These symptoms range from intense feelings of fear, anger, sadness to hyper vigilance, exaggerated startled response, irritability, difficulty in concentration and sleep problems. The psychological impact of the trauma is to strong that these symptoms continue much after the traumatic event is over. These then interfere with the normal functioning of the individual as the possible threat to life and feelings of helplessness experienced during such events trigger feelings of fear and negative appraisals regarding self, world and future.
From what you report it seems that you have not been able to recover from the horrific experience which you had undergone during earthquake. This horrific traumatizing incident has triggered symptoms of disturb sleep and of losing balance in you. My advise to you would be to continue the medication as prescribed by your psychiatrist. Psychotherapy is advisable in your case as it will help you in dealing with these symptoms and their debilitating effects. At your own level you can practice relaxation exercises like pranayam etc.