Hi I understand you are having trouble in your academics. Learning  is a process which involves encoding information into memory which happens when a stimulus is repeated over time. So adequate revision is needed to memorise anything. However this process needs good amount of concentration, a disturbance of which can cause impairment of learning. This concentration disturbance can be due to inadequate sleep, anxiety, depression, other psychiatric conditions. Please consult your Psychiatrist for evaluation and treatment. You can always direct consult me.