Hello Friend, Good that you are seeking a help here. Sleep is very essential for both physical and mental health and don't ignore such problems. Most common reason for sleep disorders is  stress and anxiety caused by poor lifestyle, work life imbalance, relationships issues or careers pressure. Just analyze where you are going wrong?. In your case, may be your body is not able to suite or adopt with the night shift routine. Take professional help to analyze and get recommendations to recover from this problem. Feel free to reach out to me online or call for further detailed evaluation and suitable recommendation. Be positive. You will be alright soon.