Exam season? Work pressure? Balance and perspective issues?
You may or may not battle with distraction.
If you do, and you are at school these days, the system might well try to bludgeon it out of you by diagnosing a deficit of attention - but they just could be missing the boat... See more on that little evergreen at :- http://www.tickertalk.co.za/blog.php?user=stuart&blogentry_id=2638
If, like most sufferers, your distraction arises from ASD - attention surplus disorder - then this little diagram from Barry Ritholz may be of interest:-