If you are currently in a rut, don't worry and be strong , it will pass', if your riding the pavement, however, beware it to will pass. Buddha-Sidharta is a river. The story is the true point of Buddhism. The only way to have a true understanding of the way we feel is to have an understanding that our emotional responses occur in a bigger picture. It is trying to say that the mind wanders.
Nothing is permanent.
If you can't concentrate it's because your worried about something and not happy with yourself. Let me know.