Hey, If your concentration issues has begun recently, there has to be a reason behind it. Firstly, let me assume that you are physically fit, well rested and haven't seen any difference in general health. Now, lack of concentration usually has 3 main reasons 1. There could be something/someone in your life which/who is engaging you at the point making it difficult for you to engage with studies. 2. You are finding it difficult to understand or apply what you have been studying 3. Your motivation level associated with studies has been lower than usual due to some reason. In any case a professional intervention could help you gain clarity on the issue & improve the attention as well as concentration. I am sure you would manage to excel at your studies in no time.