My eyes get tired after reading 1 or 2 pages, which makes me fall asleep and prevents me from studying?

Likely tension/work. This is likely to be due to being overworked or to tension. You might need a rest from your study, or a refreshing hobby that stimulates you. Exercise and time outside can be a real help, and your body will get sunlight that is very important in processing of things like vitamin d, and cleansing of skin irritants and acne. Take some time for yourself and you'd be surprised how you feel.