Well, frankly, neither do I!!!!
But, surely I can indeed give you some tips.
First of all, if you are disturbed in your mind about something, trying to study will be a futile exercise.
If your attention span is less, try meditation. I'd like to suggest a technique which I find very useful.
Close your eyes and start breathing slowly. Imagine as if you are in zero gravity. Then travel to place of your liking(a garden, forest, city, anything) and explore the place. Then slowly bring back your mind to your own surrounding. You will find yourself much refreshed and in a better mood to study.
If meditation also doesn't help, trying going for a nice walk.
Hope after following these tips, you will be able to study better. :D