I'm a 22 years old student and have been staying​ away from home (in a hostel) for the past 5 years. I can't sleep before 4-5 AM , no matter how hard I try. I don't smoke, don't drink alcohol or coffee either. Staring into phone screen for longer periods of time could be the primary reason perhaps. I try to sleep early everyday but give up after half hour or so of just lying down and thinking. Please suggest a remedy