Hi, It will be useful for you to evaluate what had caused this sudden change in your attention span ( e.g. are you distracted because you are thinking of a particular event or you are distracted in general). Observe and note down the physical sensations your body( e.g do you feel fidgtety, is your mouth dry etc.). If this problem persists for long ( incase it has an underlying biological cause) you should consult a professional ( preferably who has diagnosed you with mild ADHD before).  Good luck!