Whenever I sit down to study/revise, I always feel sleepy within 10 minutes! This has been going on for some time now, it's never happened to me before. Even if I am well rested, I will still feel this way. It's not anything to do with any of the subjects I take, I quite enjoy the subjects, I just always feel sleepy. What should I do to get rid of this? Is there any dua's/surah's that I can read that can help?