A broken sleep schedule is one of the most common student problems, and the good news is that it is fixable in about one to two weeks with a steady approach. The key idea is that your body clock is set mainly by two things, light and your wake up time. Fix those and the rest follows.
Start by choosing a realistic wake up time and holding it every single day, including weekends. Do not try to jump from waking at noon to waking at 6 am overnight. Shift by fifteen to thirty minutes earlier every two days. In the morning, get bright light immediately, ideally sunlight, because light tells your brain that the day has started and quietly resets your clock.
At night, do the opposite. Dim the lights an hour before bed and put your phone away, because screen light and endless scrolling are the two biggest reasons students cannot fall asleep. Avoid caffeine after the late afternoon, since it lingers in your body for hours. If you cannot sleep, do not lie there frustrated. Read something boring on paper until you feel drowsy, then try again.
Example: If you currently sleep at 2 am, aim for 1:30 for two nights, then 1 am, then 12:30, moving earlier gradually until you reach your target.
One practical tip: The first hour and the last hour of your day matter most. Morning light to wake the clock, no screens at night to let it wind down.