For your body to relax and get a good sleep your mind must be relaxed too.
Shut off all appliances like to , mobile 2 hours before bedtime.
Have a warm bath with aromatic oils like lavender oil before bedtime.
Drink a glass of warm milk with
sugar before you go to sleep.
Take deep breaths and calm your mind.
Since you are young I would suggest you to try all this before you take medicines.
If all this does not work take tab restyl 0.25mg once a night for 3 days only.
Consult me online if you have any problems.