Hello Rohaan

This seems to be a common problem now a days for the students. Mostly students used to feel sleepy in classroom and compromise their studies.

The foremost reason for this is the excessive usage of mobile phones. The harmful rays from the phones cause distraction to your sleeping pattern. The late night use of phone cause hindrance to your sleep and you feel lazy thorughout the day. Keep the mobile usage minimal, especially late night.

The second reason could be late night studies. Many students has a habit of studying late night, which ends up to improper sleep. You have to make proper timetable and follow it.

The third reason will be your food and eating pattern. Eating too much of oily foods and junk foods feels you lethargic all the time. Avoid eating oily foods. Keep the dinner minimal and light. 

Go for a walk or do some exercise in the morning. Yoga will keep your body energetic. Drink lots of water. 

Thank you